User equipment that determines radio link failure using timer and radio link quality, and corresponding base station

ABSTRACT

A user equipment that includes a radio transceiver that performs wireless communication in an unlicensed band, and circuitry that performs RLM using downlink physical signals, measures a radio link quality, evaluates the radio link quality against thresholds Qout and Qin, indicates out-of-sync to higher layers from a physical layer, indicates in-sync to the higher layers from the physical layer, starts a first timer when the out-of-sync is consecutively indicated to the higher layers from the physical layer, and determines that a radio link failure occurs in a case where the first timer expires without consecutive in-sync indications, and the first timer is different from a second timer used to determine whether a radio link failure occurs in a wireless communication in one or more serving cells in a licensed band.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.17/373,797, filed Jul. 13, 2021, which is a continuation of U.S.application Ser. No. 16/322,125, filed Jan. 31, 2019 (now U.S. Pat. No.11,082,988), which is based on PCT filing PCT/JP2017/023624, filed Jun.27, 2017, and claims priority to JP 2016-156464, filed in the JapanesePatent Office on Aug. 9, 2016, the entire contents of each areincorporated herein by its reference.

TECHNICAL FIELD

The present disclosure relates to a communication device, acommunication method, and a program.

BACKGROUND ART

Wireless access schemes and wireless networks of cellular mobilecommunication (hereinafter also referred to as Long Term Evolution(LTE), LTE-Advanced (LTE-A), LTE-Advanced Pro (LTE-A Pro), New Radio(NR), New Radio Access Technology (NRAT), Evolved Universal TerrestrialRadio Access (EUTRA), or Further EUTRA (FEUTRA)) are under review in 3rdGeneration Partnership Project (3GPP). Further, in the followingdescription, LTE includes LTE-A, LTE-A Pro, and EUTRA, and NR includesNRAT and FEUTRA. In LTE and NR, a base station device (base station) isalso referred to as an evolved Node B (eNodeB), and a terminal device (amobile station, a mobile station device, or a terminal) is also referredto as a user equipment (UE). LTE and NR are cellular communicationsystems in which a plurality of areas covered by a base station deviceare arranged in a cell form. A single base station device may manage aplurality of cells.

LAA is one technology of LTE and a scheme of performing an LTE operationin an unlicensed band. In LAA, coexistence of other nodes or wirelesssystems is important and a function such as discontinuous transmissionor Listen Before Talk (LBT) in which sensing of channels is performedbefore transmission is requested. The details of LAA are disclosed inNon-Patent Literature 1.

NR is a different Radio Access Technology (RAT) from LTE as a wirelessaccess scheme of the next generation of LTE. NR is an access technologycapable of handling various use cases including Enhanced Mobilebroadband (eMBB), Massive Machine Type Communications (mMTC), and ultrareliable and Low Latency Communications (URLLC). NR is reviewed for thepurpose of a technology framework corresponding to use scenarios,request conditions, placement scenarios, and the like in such use cases.The details of the scenarios or request conditions of NR are disclosedin Non-Patent Literature 1.

CITATION LIST Non-Patent Literature

-   Non-Patent Literature 1: 3rd Generation Partnership Project;    Technical Specification Group Radio Access Network; Study on    Licensed-Assisted Access to Unlicensed Spectrum; (Release 13), 3GPP    TR 36.889 v13.0.0 (2015 June).

DISCLOSURE OF INVENTION Technical Problem

Incidentally, in LTE operated in a licensed band, downlinksynchronization and Radio Link Monitoring (RLM) measurement areperformed on the basis of a reference signal transmitted with downlinkwireless resources in all sub frames. On the other hand, in LAA or NR,the reference signal is not included in downlink wireless resourcesduring all the unit periods such as so-called sub frames and thereference signal is not included in the downlink wireless resources insome of the unit periods in some cases. Therefore, in LAA or NR,terminal devices may not always detect the reference signal during allthe unit periods and it is difficult to perform stable downlinksynchronization or RLM measurement in some cases.

Accordingly, the present disclosure proposes a communication device, acommunication method, and a program capable of realizing more stablesynchronization or RLM measurement even in a situation in which areference signal is not necessarily transmitted during all unit periods.

Solution to Problem

According to the present disclosure, there is provided a communicationdevice including: a communication unit configured to perform wirelesscommunication; and an acquisition unit configured to acquire informationregarding communication quality of the wireless communication targetinga period in which a reference signal is transmitted on the basis of thereference signal that is discontinuously transmitted.

In addition, according to the present disclosure, there is provided acommunication device including: a communication unit configured toperform wireless communication; and a control unit configured to controla reference signal that is discontinuously transmitted and used tomeasure communication quality of the wireless communication such thatinformation for directly or indirectly specifying a period in which thereference signal is transmitted is transmitted to a terminal device.

In addition, according to the present disclosure, there is provided acommunication method including: performing wireless communication; andacquiring, by a computer, information regarding communication quality ofthe wireless communication targeting a period in which a referencesignal is transmitted on the basis of the reference signal that isdiscontinuously transmitted.

In addition, according to the present disclosure, there is provided acommunication method including: performing wireless communication; andcontrolling, by a computer, a reference signal that is discontinuouslytransmitted and used to measure communication quality of the wirelesscommunication such that information for directly or indirectlyspecifying a period in which the reference signal is transmitted istransmitted to a terminal device.

In addition, according to the present disclosure, there is provided aprogram causing a computer to: perform wireless communication; andacquire information regarding communication quality of the wirelesscommunication targeting a period in which a reference signal istransmitted on the basis of the reference signal that is discontinuouslytransmitted.

In addition, according to the present disclosure, there is provided aprogram causing a computer to: perform wireless communication; andcontrol a reference signal that is discontinuously transmitted and usedto measure communication quality of the wireless communication such thatinformation for directly or indirectly specifying a period in which thereference signal is transmitted is transmitted to a terminal device.

Advantageous Effects of Invention

According to the present disclosure, as described above, it is possibleto provide a communication device, a communication method, and a programcapable of realizing more stable downlink synchronization or RLMmeasurement even in a situation in which a reference signal is notincluded in downlink wireless resources during all unit periods.

Note that the effects described above are not necessarily limitative.With or in the place of the above effects, there may be achieved any oneof the effects described in this specification or other effects that maybe grasped from this specification.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating an example of setting of a componentcarrier according to an embodiment of the present disclosure.

FIG. 2 is a diagram illustrating an example of setting of a componentcarrier according to the embodiment.

FIG. 3 is a diagram illustrating an example of a downlink sub frame ofLTE according to the embodiment.

FIG. 4 is a diagram illustrating an example of an uplink sub frame ofLTE according to the embodiment.

FIG. 5 is a diagram illustrating examples of parameter sets related to atransmission signal in an NR cell.

FIG. 6 is a diagram illustrating an example of an NR downlink sub frameof the embodiment.

FIG. 7 is a diagram illustrating an example of an NR uplink sub frame ofthe embodiment.

FIG. 8 is a schematic block diagram illustrating a configuration of abase station device of the embodiment.

FIG. 9 is a schematic block diagram illustrating a configuration of aterminal device of the embodiment.

FIG. 10 is a diagram illustrating an example of downlink resourceelement mapping of LTE according to the embodiment.

FIG. 11 is a diagram illustrating an example of downlink resourceelement mapping of NR according to the embodiment.

FIG. 12 is a diagram illustrating an example of downlink resourceelement mapping of NR according to the embodiment.

FIG. 13 is a diagram illustrating an example of downlink resourceelement mapping of NR according to the embodiment.

FIG. 14 is a diagram illustrating an example of a frame configuration ofa self-contained transmission according to the embodiment.

FIG. 15 is an explanatory diagram illustrating examples of a timevariation of radio link quality and each of an in-synchronization stateand an out-of-synchronization state.

FIG. 16 is an explanatory diagram illustrating an example oftransmission of a reference signal used to measure downlink radio linkquality.

FIG. 17 is a block diagram illustrating a first example of a schematicconfiguration of an eNB.

FIG. 18 is a block diagram illustrating a second example of theschematic configuration of the eNB.

FIG. 19 is a block diagram illustrating an example of a schematicconfiguration of a smartphone.

FIG. 20 is a block diagram illustrating an example of a schematicconfiguration of a car navigation apparatus.

MODE(S) FOR CARRYING OUT THE INVENTION

Hereinafter, (a) preferred embodiment(s) of the present disclosure willbe described in detail with reference to the appended drawings. Notethat, in this specification and the appended drawings, structuralelements that have substantially the same function and structure aredenoted with the same reference numerals, and repeated explanation ofthese structural elements is omitted.

Note that the description will be made in the following order.

1. Embodiment 1.1. Overview

1.2. Wireless frame configuration1.3. Channel and signal

1.4. Configuration

1.5. Control information and control channel

1.6. CA and DC

1.7. Resource allocation1.8. Error correction1.9. Resource element mapping1.10. Self-contained transmission1.11. Technical features2. Application examples2.1. Application example related to base station2.2. Application example related to terminal device

3. Conclusion 1. EMBODIMENT 1.1. Overview

Hereinafter, (a) preferred embodiment(s) of the present disclosure willbe described in detail with reference to the appended drawings. Notethat, in this specification and the appended drawings, structuralelements that have substantially the same function and structure aredenoted with the same reference numerals, and repeated explanation ofthese structural elements is omitted. Further, technologies, functions,methods, configurations, and procedures to be described below and allother descriptions can be applied to LTE and NR unless particularlystated otherwise.

<Wireless Communication System in the Present Embodiment>

In the present embodiment, a wireless communication system includes atleast a base station device 1 and a terminal device 2. The base stationdevice 1 can accommodate multiple terminal devices. The base stationdevice 1 can be connected with another base station device by means ofan X2 interface. Further, the base station device 1 can be connected toan evolved packet core (EPC) by means of an S1 interface. Further, thebase station device 1 can be connected to a mobility management entity(MME) by means of an S1-MME interface and can be connected to a servinggateway (S-GW) by means of an S1-U interface. The S1 interface supportsmany-to-many connection between the MME and/or the S-GW and the basestation device 1. Further, in the present embodiment, the base stationdevice 1 and the terminal device 2 each support LTE and/or NR.

<Wireless Access Technology According to Present Embodiment>

In the present embodiment, the base station device 1 and the terminaldevice 2 each support one or more wireless access technologies (RATs).For example, an RAT includes LTE and NR. A single RAT corresponds to asingle cell (component carrier). That is, in a case in which a pluralityof RATs is supported, the RATs each correspond to different cells. Inthe present embodiment, a cell is a combination of a downlink resource,an uplink resource, and/or a sidelink. Further, in the followingdescription, a cell corresponding to LTE is referred to as an LTE celland a cell corresponding to NR is referred to as an NR cell.

Downlink communication is communication from the base station device 1to the terminal device 2. Downlink transmission is transmission from thebase station device 1 to the terminal device 2 and is transmission of adownlink physical channel and/or a downlink physical signal. Uplinkcommunication is communication from the terminal device 2 to the basestation device 1. Uplink transmission is transmission from the terminaldevice 2 to the base station device 1 and is transmission of an uplinkphysical channel and/or an uplink physical signal. Sidelinkcommunication is communication from the terminal device 2 to anotherterminal device 2. Sidelink transmission is transmission from theterminal device 2 to another terminal device 2 and is transmission of asidelink physical channel and/or a sidelink physical signal.

The sidelink communication is defined for contiguous direct detectionand contiguous direct communication between terminal devices. Thesidelink communication, a frame configuration similar to that of theuplink and downlink can be used. Further, the sidelink communication canbe restricted to some (sub sets) of uplink resources and/or downlinkresources.

The base station device 1 and the terminal device 2 can supportcommunication in which a set of one or more cells is used in a downlink,an uplink, and/or a sidelink. Communication using a set of a pluralityof cells or a set of a plurality of cells is also referred to as carrieraggregation or dual connectivity. The details of the carrier aggregationand the dual connectivity will be described below. Further, each celluses a predetermined frequency bandwidth. A maximum value, a minimumvalue, and a settable value in the predetermined frequency bandwidth canbe specified in advance.

FIG. 1 is a diagram illustrating an example of setting of a componentcarrier according to the present embodiment. In the example of FIG. 1 ,one LTE cell and two NR cells are set. One LTE cell is set as a primarycell. Two NR cells are set as a primary secondary cell and a secondarycell. Two NR cells are integrated by the carrier aggregation. Further,the LTE cell and the NR cell are integrated by the dual connectivity.Note that the LTE cell and the NR cell may be integrated by carrieraggregation. In the example of FIG. 1 , NR may not support somefunctions such as a function of performing standalone communicationsince connection can be assisted by an LTE cell which is a primary cell.The function of performing standalone communication includes a functionnecessary for initial connection.

FIG. 2 is a diagram illustrating an example of setting of a componentcarrier according to the present embodiment. In the example of FIG. 2 ,two NR cells are set. The two NR cells are set as a primary cell and asecondary cell, respectively, and are integrated by carrier aggregation.In this case, when the NR cell supports the function of performingstandalone communication, assist of the LTE cell is not necessary. Notethat the two NR cells may be integrated by dual connectivity.

1.2. Radio Frame Configuration <Radio Frame Configuration in PresentEmbodiment>

In the present embodiment, a radio frame configured with 10 ms(milliseconds) is specified. Each radio frame includes two half frames.A time interval of the half frame is 5 ms. Each half frame includes 5sub frames. The time interval of the sub frame is 1 ms and is defined bytwo successive slots. The time interval of the slot is 0.5 ms. An i-thsub frame in the radio frame includes a (2×i)-th slot and a (2×i+1)-thslot. In other words, 10 sub frames are specified in each of the radioframes.

Sub frames include a downlink sub frame, an uplink sub frame, a specialsub frame, a sidelink sub frame, and the like.

The downlink sub frame is a sub frame reserved for downlinktransmission. The uplink sub frame is a sub frame reserved for uplinktransmission. The special sub frame includes three fields. The threefields are a Downlink Pilot Time Slot (DwPTS), a Guard Period (GP), andan Uplink Pilot Time Slot (UpPTS). A total length of DwPTS, GP, andUpPTS is 1 ms. The DwPTS is a field reserved for downlink transmission.The UpPTS is a field reserved for uplink transmission. The GP is a fieldin which downlink transmission and uplink transmission are notperformed. Further, the special sub frame may include only the DwPTS andthe GP or may include only the GP and the UpPTS. The special sub frameis placed between the downlink sub frame and the uplink sub frame in TDDand used to perform switching from the downlink sub frame to the uplinksub frame. The sidelink sub frame is a sub frame reserved or set forsidelink communication. The sidelink is used for contiguous directcommunication and contiguous direct detection between terminal devices.

A single radio frame includes a downlink sub frame, an uplink sub frame,a special sub frame, and/or a sidelink sub frame. Further, a singleradio frame includes only a downlink sub frame, an uplink sub frame, aspecial sub frame, or a sidelink sub frame.

A plurality of radio frame configurations is supported. The radio frameconfiguration is specified by the frame configuration type. The frameconfiguration type 1 can be applied only to FDD. The frame configurationtype 2 can be applied only to TDD. The frame configuration type 3 can beapplied only to an operation of a licensed assisted access (LAA)secondary cell.

In the frame configuration type 2, a plurality of uplink-downlinkconfigurations is specified. In the uplink-downlink configuration, eachof 10 sub frames in one radio frame corresponds to one of the downlinksub frame, the uplink sub frame, and the special sub frame. The subframe 0, the sub frame 5 and the DwPTS are constantly reserved fordownlink transmission. The UpPTS and the sub frame just after thespecial sub frame are constantly reserved for uplink transmission.

In the frame configuration type 3, 10 sub frames in one radio frame arereserved for downlink transmission. The terminal device 2 treats a subframe by which PDSCH or a detection signal is not transmitted, as anempty sub frame. Unless a predetermined signal, channel and/or downlinktransmission is detected in a certain sub frame, the terminal device 2assumes that there is no signal and/or channel in the sub frame. Thedownlink transmission is exclusively occupied by one or more consecutivesub frames. The first sub frame of the downlink transmission may bestarted from any one in that sub frame. The last sub frame of thedownlink transmission may be either completely exclusively occupied orexclusively occupied by a time interval specified in the DwPTS.

Further, in the frame configuration type 3, 10 sub frames in one radioframe may be reserved for uplink transmission. Further, each of 10 subframes in one radio frame may correspond to any one of the downlink subframe, the uplink sub frame, the special sub frame, and the sidelink subframe.

The base station device 1 may transmit a downlink physical channel and adownlink physical signal in the DwPTS of the special sub frame. The basestation device 1 can restrict transmission of the PBCH in the DwPTS ofthe special sub frame. The terminal device 2 may transmit uplinkphysical channels and uplink physical signals in the UpPTS of thespecial sub frame. The terminal device 2 can restrict transmission ofsome of the uplink physical channels and the uplink physical signals inthe UpPTS of the special sub frame.

Note that a time interval in single transmission is referred to as atransmission time interval (TTI) and 1 ms (1 sub frame) is defined as 1TTI in LTE.

<Frame Configuration of LTE in Present Embodiment>

FIG. 3 is a diagram illustrating an example of a downlink sub frame ofLTE according to the present embodiment. The diagram illustrated in FIG.3 is referred to as a downlink resource grid of LTE. The base stationdevice 1 can transmit a downlink physical channel of LTE and/or adownlink physical signal of LTE in a downlink sub frame to the terminaldevice 2. The terminal device 2 can receive a downlink physical channelof LTE and/or a downlink physical signal of LTE in a downlink sub framefrom the base station device 1.

FIG. 4 is a diagram illustrating an example of an uplink sub frame ofLTE according to the present embodiment. The diagram illustrated in FIG.4 is referred to as an uplink resource grid of LTE. The terminal device2 can transmit an uplink physical channel of LTE and/or an uplinkphysical signal of LTE in an uplink sub frame to the base station device1. The base station device 1 can receive an uplink physical channel ofLTE and/or an uplink physical signal of LTE in an uplink sub frame fromthe terminal device 2.

In the present embodiment, the LTE physical resources can be defined asfollows. One slot is defined by a plurality of symbols. The physicalsignal or the physical channel transmitted in each of the slots isrepresented by a resource grid. In the downlink, the resource grid isdefined by a plurality of sub carriers in a frequency direction and aplurality of OFDM symbols in a time direction. In the uplink, theresource grid is defined by a plurality of sub carriers in the frequencydirection and a plurality of SC-FDMA symbols in the time direction. Thenumber of sub carriers or the number of resource blocks may be decideddepending on a bandwidth of a cell. The number of symbols in one slot isdecided by a type of cyclic prefix (CP). The type of CP is a normal CPor an extended CP. In the normal CP, the number of OFDM symbols orSC-FDMA symbols constituting one slot is 7. In the extended CP, thenumber of OFDM symbols or SC-FDMA symbols constituting one slot is 6.Each element in the resource grid is referred to as a resource element.The resource element is identified using an index (number) of a subcarrier and an index (number) of a symbol. Further, in the descriptionof the present embodiment, the OFDM symbol or SC-FDMA symbol is alsoreferred to simply as a symbol.

The resource blocks are used for mapping a certain physical channel (thePDSCH, the PUSCH, or the like) to resource elements. The resource blocksinclude virtual resource blocks and physical resource blocks. A certainphysical channel is mapped to a virtual resource block. The virtualresource blocks are mapped to physical resource blocks. One physicalresource block is defined by a predetermined number of consecutivesymbols in the time domain. One physical resource block is defined froma predetermined number of consecutive sub carriers in the frequencydomain. The number of symbols and the number of sub carriers in onephysical resource block are decided on the basis of a parameter set inaccordance with a type of CP, a sub carrier interval, and/or a higherlayer in the cell. For example, in a case in which the type of CP is thenormal CP, and the sub carrier interval is 15 kHz, the number of symbolsin one physical resource block is 7, and the number of sub carriers is12. In this case, one physical resource block includes (7×12) resourceelements. The physical resource blocks are numbered from 0 in thefrequency domain. Further, two resource blocks in one sub framecorresponding to the same physical resource block number are defined asa physical resource block pair (a PRB pair or an RB pair).

In each LTE cell, one predetermined parameter is used in a certain subframe. For example, the predetermined parameter is a parameter (physicalparameter) related to a transmission signal. Parameters related to thetransmission signal include a CP length, a sub carrier interval, thenumber of symbols in one sub frame (predetermined time length), thenumber of sub carriers in one resource block (predetermined frequencyband), a multiple access scheme, a signal waveform, and the like.

That is, in the LTE cell, a downlink signal and an uplink signal areeach generated using one predetermined parameter in a predetermined timelength (for example, a sub frame). In other words, in the terminaldevice 2, it is assumed that a downlink signal to be transmitted fromthe base station device 1 and an uplink signal to be transmitted to thebase station device 1 are each generated with a predetermined timelength with one predetermined parameter. Further, the base stationdevice 1 is set such that a downlink signal to be transmitted to theterminal device 2 and an uplink signal to be transmitted from theterminal device 2 are each generated with a predetermined time lengthwith one predetermined parameter.

<Frame Configuration of NR in Present Embodiment>

In each NR cell, one or more predetermined parameters are used in acertain predetermined time length (for example, a sub frame). That is,in the NR cell, a downlink signal and an uplink signal are eachgenerated using or more predetermined parameters in a predetermined timelength. In other words, in the terminal device 2, it is assumed that adownlink signal to be transmitted from the base station device 1 and anuplink signal to be transmitted to the base station device 1 are eachgenerated with one or more predetermined parameters in a predeterminedtime length. Further, the base station device 1 is set such that adownlink signal to be transmitted to the terminal device 2 and an uplinksignal to be transmitted from the terminal device 2 are each generatedwith a predetermined time length using one or more predeterminedparameters. In a case in which the plurality of predetermined parametersare used, a signal generated using the predetermined parameters ismultiplexed in accordance with a predetermined method. For example, thepredetermined method includes Frequency Division Multiplexing (FDM),Time Division Multiplexing (TDM), Code Division Multiplexing (CDM),and/or Spatial Division Multiplexing (SDM).

In a combination of the predetermined parameters set in the NR cell, aplurality of kinds of parameter sets can be specified in advance.

FIG. 5 is a diagram illustrating examples of the parameter sets relatedto a transmission signal in the NR cell. In the example of FIG. 5 ,parameters of the transmission signal included in the parameter setsinclude a sub carrier interval, the number of sub carriers per resourceblock in the NR cell, the number of symbols per sub frame, and a CPlength type. The CP length type is a type of CP length used in the NRcell. For example, CP length type 1 is equivalent to a normal CP in LTEand CP length type 2 is equivalent to an extended CP in LTE.

The parameter sets related to a transmission signal in the NR cell canbe specified individually with a downlink and an uplink. Further, theparameter sets related to a transmission signal in the NR cell can beset independently with a downlink and an uplink.

FIG. 6 is a diagram illustrating an example of an NR downlink sub frameof the present embodiment. In the example of FIG. 6 , signals generatedusing parameter set 1, parameter set 0, and parameter set 2 aresubjected to FDM in a cell (system bandwidth). The diagram illustratedin FIG. 6 is also referred to as a downlink resource grid of NR. Thebase station device 1 can transmit the downlink physical channel of NRand/or the downlink physical signal of NR in a downlink sub frame to theterminal device 2. The terminal device 2 can receive a downlink physicalchannel of NR and/or the downlink physical signal of NR in a downlinksub frame from the base station device 1.

FIG. 7 is a diagram illustrating an example of an NR uplink sub frame ofthe present embodiment. In the example of FIG. 7 , signals generatedusing parameter set 1, parameter set 0, and parameter set 2 aresubjected to FDM in a cell (system bandwidth). The diagram illustratedin FIG. 6 is also referred to as an uplink resource grid of NR. The basestation device 1 can transmit the uplink physical channel of NR and/orthe uplink physical signal of NR in an uplink sub frame to the terminaldevice 2. The terminal device 2 can receive an uplink physical channelof NR and/or the uplink physical signal of NR in an uplink sub framefrom the base station device 1.

<Antenna Port in Present Embodiment>

An antenna port is defined so that a propagation channel carrying acertain symbol can be inferred from a propagation channel carryinganother symbol in the same antenna port. For example, different physicalresources in the same antenna port can be assumed to be transmittedthrough the same propagation channel. In other words, for a symbol in acertain antenna port, it is possible to estimate and demodulate apropagation channel in accordance with the reference signal in theantenna port. Further, there is one resource grid for each antenna port.The antenna port is defined by the reference signal. Further, eachreference signal can define a plurality of antenna ports.

The antenna port is specified or identified with an antenna port number.For example, antenna ports 0 to 3 are antenna ports with which CRS istransmitted. That is, the PDSCH transmitted with antenna ports 0 to 3can be demodulated to CRS corresponding to antenna ports 0 to 3.

In a case in which two antenna ports satisfy a predetermined condition,the two antenna ports can be regarded as being a quasi co-location(QCL). The predetermined condition is that a wide area characteristic ofa propagation channel carrying a symbol in one antenna port can beinferred from a propagation channel carrying a symbol in another antennaport. The wide area characteristic includes a delay dispersion, aDoppler spread, a Doppler shift, an average gain, and/or an averagedelay.

In the present embodiment, the antenna port numbers may be defineddifferently for each RAT or may be defined commonly between RATs. Forexample, antenna ports 0 to 3 in LTE are antenna ports with which CRS istransmitted. In the NR, antenna ports 0 to 3 can be set as antenna portswith which CRS similar to that of LTE is transmitted. Further, in NR,the antenna ports with which CRS is transmitted like LTE can be set asdifferent antenna port numbers from antenna ports 0 to 3. In thedescription of the present embodiment, predetermined antenna portnumbers can be applied to LTE and/or NR.

1.3. Channel and Signal <Physical Channel and Physical Signal in PresentEmbodiment>

In the present embodiment, physical channels and physical signals areused. The physical channels include a downlink physical channel, anuplink physical channel, and a sidelink physical channel. The physicalsignals include a downlink physical signal, an uplink physical signal,and a sidelink physical signal.

In LTE, a physical channel and a physical signal are referred to as anLTE physical channel and an LTE physical signal. In NR, a physicalchannel and a physical signal are referred to as an NR physical channeland an NR physical signal. The LTE physical channel and the NR physicalchannel can be defined as different physical channels, respectively. TheLTE physical signal and the NR physical signal can be defined asdifferent physical signals, respectively. In the description of thepresent embodiment, the LTE physical channel and the NR physical channelare also simply referred to as physical channels, and the LTE physicalsignal and the NR physical signal are also simply referred to asphysical signals. That is, the description of the physical channels canbe applied to any of the LTE physical channel and the NR physicalchannel. The description of the physical signals can be applied to anyof the LTE physical signal and the NR physical signal.

<NR Physical Channel and NR Physical Signal in Present Embodiment>

The description of the physical channel and the physical signal in theLTED can also be applied to the NR physical channel and the NR physicalsignal, respectively. The NR physical channel and the NR physical signalare referred to as the following.

The NR uplink physical channel includes an NR-PUSCH (Physical UplinkShared Channel), an NR-PUCCH (Physical Uplink Control Channel), anNR-PRACH (Physical Random Access Channel), and the like.

The NR physical downlink signal includes an NR-SS, an NR-DL-RS, anNR-DS, and the like. The NR-SS includes an NR-PSS, an NR-SSS, and thelike. The NR-RS includes an NR-CRS, an NR-PDSCH-DMRS, an NR-EPDCCH-DMRS,an NR-PRS, an NR-CSI-RS, an NR-TRS, and the like.

The NR physical uplink channel includes an NR-PUSCH, an NR-PUCCH, anNR-PRACH, and the like.

The NR physical uplink signal includes an NR-UL-RS. The NR-UL-RSincludes an NR-UL-DMRS, an NR-SRS, and the like.

The NR physical sidelink channel includes an NR-PSBCH, an NR-PSCCH, anNR-PSDCH, an NR-PSSCH, and the like.

<Downlink Physical Channel in Present Embodiment>

The PBCH is used to broadcast a master information block (MIB) which isbroadcast information specific to a serving cell of the base stationdevice 1. The PBCH is transmitted only through the sub frame 0 in theradio frame. The MIB can be updated at intervals of 40 ms. The PBCH isrepeatedly transmitted with a cycle of 10 ms. Specifically, initialtransmission of the MIB is performed in the sub frame 0 in the radioframe satisfying a condition that a remainder obtained by dividing asystem frame number (SFN) by 4 is 0, and retransmission (repetition) ofthe MIB is performed in the sub frame 0 in all the other radio frames.The SFN is a radio frame number (system frame number). The MIB is systeminformation. For example, the MIB includes information indicating theSFN.

The PCFICH is used to transmit information related to the number of OFDMsymbols used for transmission of the PDCCH. A region indicated by PCFICHis also referred to as a PDCCH region. The information transmittedthrough the PCFICH is also referred to as a control format indicator(CFI).

The PHICH is used to transmit an HARQ-ACK (an HARQ indicator, HARQfeedback, response information, and HARQ (Hybrid Automatic Repeatrequest)) indicating ACKnowledgment (ACK) or negative ACKnowledgment(NACK) of uplink data (an uplink shared channel (UL-SCH)) received bythe base station device 1. For example, in a case in which the HARQ-ACKindicating ACK is received by the terminal device 2, correspondinguplink data is not retransmitted. For example, in a case in which theterminal device 2 receives the HARQ-ACK indicating NACK, the terminaldevice 2 retransmits corresponding uplink data through a predetermineduplink sub frame. A certain PHICH transmits the HARQ-ACK for certainuplink data. The base station device 1 transmits each HARQ-ACK to aplurality of pieces of uplink data included in the same PUSCH using aplurality of PHICHs.

The PDCCH and the EPDCCH are used to transmit downlink controlinformation (DCI). Mapping of an information bit of the downlink controlinformation is defined as a DCI format. The downlink control informationincludes a downlink grant and an uplink grant. The downlink grant isalso referred to as a downlink assignment or a downlink allocation.

The PDCCH is transmitted by a set of one or more consecutive controlchannel elements (CCEs). The CCE includes 9 resource element groups(REGs). An REG includes 4 resource elements. In a case in which thePDCCH is constituted by n consecutive CCEs, the PDCCH starts with a CCEsatisfying a condition that a remainder after dividing an index (number)i of the CCE by n is 0.

The EPDCCH is transmitted by a set of one or more consecutive enhancedcontrol channel elements (ECCEs). The ECCE is constituted by a pluralityof enhanced resource element groups (EREGs).

The downlink grant is used for scheduling of the PDSCH in a certaincell. The downlink grant is used for scheduling of the PDSCH in the samesub frame as a sub frame in which the downlink grant is transmitted. Theuplink grant is used for scheduling of the PUSCH in a certain cell. Theuplink grant is used for scheduling of a single PUSCH in a fourth subframe from a sub frame in which the uplink grant is transmitted orlater.

A cyclic redundancy check (CRC) parity bit is added to the DCI. The CRCparity bit is scrambled using a radio network temporary identifier(RNTI). The RNTI is an identifier that can be specified or set inaccordance with a purpose of the DCI or the like. The RNTI is anidentifier specified in a specification in advance, an identifier set asinformation specific to a cell, an identifier set as informationspecific to the terminal device 2, or an identifier set as informationspecific to a group to which the terminal device 2 belongs. For example,in monitoring of the PDCCH or the EPDCCH, the terminal device 2descrambles the CRC parity bit added to the DCI with a predeterminedRNTI and identifies whether or not the CRC is correct. In a case inwhich the CRC is correct, the DCI is understood to be a DCI for theterminal device 2.

The PDSCH is used to transmit downlink data (a downlink shared channel(DL-SCH)). Further, the PDSCH is also used to transmit controlinformation of a higher layer.

The PMCH is used to transmit multicast data (a multicast channel (MCH)).

In the PDCCH region, a plurality of PDCCHs may be multiplexed accordingto frequency, time, and/or space. In the EPDCCH region, a plurality ofEPDCCHs may be multiplexed according to frequency, time, and/or space.In the PDSCH region, a plurality of PDSCHs may be multiplexed accordingto frequency, time, and/or space. The PDCCH, the PDSCH, and/or theEPDCCH may be multiplexed according to frequency, time, and/or space.

<Downlink Physical Signal in Present Embodiment>

A synchronization signal is used for the terminal device 2 to obtaindownlink synchronization in the frequency domain and/or the time domain.The synchronization signal includes a primary synchronization signal(PSS) and a secondary synchronization signal (SSS). The synchronizationsignal is placed in a predetermined sub frame in the radio frame. Forexample, in the TDD scheme, the synchronization signal is placed in thesub frames 0, 1, 5, and 6 in the radio frame. In the FDD scheme, thesynchronization signal is placed in the sub frames 0 and 5 in the radioframe.

The PSS may be used for coarse frame/symbol timing synchronization(synchronization in the time domain) or identification of a cellidentification group. The SSS may be used for more accurate frame timingsynchronization, cell identification, or CP length detection. In otherwords, frame timing synchronization and cell identification can beperformed using the PSS and the SSS.

The downlink reference signal is used for the terminal device 2 toperform propagation path estimation of the downlink physical channel,propagation path correction, calculation of downlink channel stateinformation (CSI), and/or measurement of positioning of the terminaldevice 2.

The CRS is transmitted in the entire band of the sub frame. The CRS isused for receiving (demodulating) the PBCH, the PDCCH, the PHICH, thePCFICH, and the PDSCH. The CRS may be used for the terminal device 2 tocalculate the downlink channel state information. The PBCH, the PDCCH,the PHICH, and the PCFICH are transmitted through the antenna port usedfor transmission of the CRS. The CRS supports the antenna portconfigurations of 1, 2, or 4. The CRS is transmitted through one or moreof the antenna ports 0 to 3.

The URS associated with the PDSCH is transmitted through a sub frame anda band used for transmission of the PDSCH with which the URS isassociated. The URS is used for demodulation of the PDSCH to which theURS is associated. The URS associated with the PDSCH is transmittedthrough one or more of the antenna ports 5 and 7 to 14.

The PDSCH is transmitted through an antenna port used for transmissionof the CRS or the URS on the basis of the transmission mode and the DCIformat. A DCI format 1A is used for scheduling of the PDSCH transmittedthrough an antenna port used for transmission of the CRS. A DCI format2D is used for scheduling of the PDSCH transmitted through an antennaport used for transmission of the URS.

The DMRS associated with the EPDCCH is transmitted through a sub frameand a band used for transmission of the EPDCCH to which the DMRS isassociated. The DMRS is used for demodulation of the EPDCCH with whichthe DMRS is associated. The EPDCCH is transmitted through an antennaport used for transmission of the DMRS. The DMRS associated with theEPDCCH is transmitted through one or more of the antenna ports 107 to114.

The CSI-RS is transmitted through a set sub frame. The resources inwhich the CSI-RS is transmitted are set by the base station device 1.The CSI-RS is used for the terminal device 2 to calculate the downlinkchannel state information. The terminal device 2 performs signalmeasurement (channel measurement) using the CSI-RS. The CSI-RS supportssetting of some or all of the antenna ports 1, 2, 4, 8, 12, 16, 24, and32. The CSI-RS is transmitted through one or more of the antenna ports15 to 46. Further, an antenna port to be supported may be decided on thebasis of a terminal device capability of the terminal device 2, settingof an RRC parameter, and/or a transmission mode to be set.

Resources of the ZP CSI-RS are set by a higher layer. Resources of theZP CSI-RS may be transmitted with zero output power. In other words, theresources of the ZP CSI-RS may transmit nothing. The ZP PDSCH and theEPDCCH are not transmitted in the resources in which the ZP CSI-RS isset. For example, the resources of the ZP CSI-RS are used for a neighborcell to transmit the NZP CSI-RS. Further, for example, the resources ofthe ZP CSI-RS are used to measure the CSI-IM. Further, for example, theresources of the ZP CSI-RS are resources with which a predeterminedchannel such as the PDSCH is not transmitted. In other words, thepredetermined channel is mapped (to be rate-matched or punctured) exceptfor the resources of the ZP CSI-RS. Note that, in the presentembodiment, the CSI-RS is regarded as a nonzero-power (NZP) CSI-RSunless it is described as a ZP CSI-RS.

A discovery signal (DS) is transmitted in order for the terminal deviceto discover a cell and perform RRM measurement. The DS includes one tofive consecutive sub frames in frame configuration type 1 (FDD), two tofive consecutive sub frames in frame configuration type 2 (TDD), andtwelve consecutive OFDM symbols in a sub frame which is targeted as onenonempty sub frame (in which one signal is transmitted) in frameconfiguration type 3 (LAA). The DS includes a CRS, a PSS, and an SSStransmitted with antenna port 0 and 0 or more nonzero-power CSI-RSs. Inthe terminal device, a discovery measurement timing configuration (DMTC)is set by a dedicated RRC. In the DMTC, a period, an offset, and a DMTCsection are set. The CRS in the DS is included in all the downlink subframes and the DwPTS in the DS section. The PSS in the DS is included inhead sub frames in the DS sections in frame configuration type 1 (FDD)and frame configuration type 3 (LAA). In addition, the PSS in the DS isincluded in the second sub frame in the DS section in frameconfiguration type 2 (TDD). The SSS in the DS is included in the headsub frame in the DS section. The nonzero-power CSI-RS in the DS isincluded in a sub frame based on offset information from the SSS setfrom a higher layer.

<Uplink Physical Signal in Present Embodiment>

The PUCCH is a physical channel used for transmitting uplink controlinformation (UCI). The uplink control information includes downlinkchannel state information (CSI), a scheduling request (SR) indicating arequest for PUSCH resources, and a HARQ-ACK to downlink data (atransport block (TB) or a downlink-shared channel (DL-SCH)). TheHARQ-ACK is also referred to as ACK/NACK, HARQ feedback, or responseinformation. Further, the HARQ-ACK to downlink data indicates ACK, NACK,or DTX.

The PUSCH is a physical channel used for transmitting uplink data(uplink-shared channel (UL-SCH)). Further, the PUSCH may be used totransmit the HARQ-ACK and/or the channel state information together withuplink data. Further, the PUSCH may be used to transmit only the channelstate information or only the HARQ-ACK and the channel stateinformation.

The PRACH is a physical channel used for transmitting a random accesspreamble. The PRACH can be used for the terminal device 2 to obtainsynchronization in the time domain with the base station device 1.Further, the PRACH is also used to indicate an initial connectionestablishment procedure (process), a handover procedure, a connectionre-establishment procedure, synchronization (timing adjustment) foruplink transmission, and/or a request for PUSCH resources.

In the PUCCH region, a plurality of PUCCHs is frequency, time, space,and/or code multiplexed. In the PUSCH region, a plurality of PUSCHs maybe frequency, time, space, and/or code multiplexed. The PUCCH and thePUSCH may be frequency, time, space, and/or code multiplexed. The PRACHmay be placed over a single sub frame or two sub frames. A plurality ofPRACHs may be code-multiplexed.

<Physical Resources for Control Channel in Present Embodiment>

A resource element group (REG) is used to define mapping of the resourceelement and the control channel. For example, the REG is used formapping of the PDCCH, the PHICH, or the PCFICH. The REG is constitutedby four consecutive resource elements which are in the same OFDM symboland not used for the CRS in the same resource block. Further, the REG isconstituted by first to fourth OFDM symbols in a first slot in a certainsub frame.

An enhanced resource element group (EREG) is used to define mapping ofthe resource elements and the enhanced control channel. For example, theEREG is used for mapping of the EPDCCH. One resource block pair isconstituted by 16 EREGs. Each EREG is assigned the number of 0 to 15 foreach resource block pair. Each EREG is constituted by 9 resourceelements excluding resource elements used for the DM-RS associated withthe EPDCCH in one resource block pair.

1.4. Configuration <Configuration Example of Base Station Device 1 inPresent Embodiment>

FIG. 8 is a schematic block diagram illustrating a configuration of thebase station device 1 of the present embodiment. As illustrated, thebase station device 1 includes a higher layer processing unit 101, acontrol unit 103, a receiving unit 105, a transmitting unit 107, and atransceiving antenna 109. Further, the receiving unit 105 includes adecoding unit 1051, a demodulating unit 1053, a demultiplexing unit1055, a wireless receiving unit 1057, and a channel measuring unit 1059.Further, the transmitting unit 107 includes an encoding unit 1071, amodulating unit 1073, a multiplexing unit 1075, a wireless transmittingunit 1077, and a downlink reference signal generating unit 1079.

As described above, the base station device 1 can support one or moreRATs. Some or all of the units included in the base station device 1illustrated in FIG. 8 can be configured individually in accordance withthe RAT. For example, the receiving unit 105 and the transmitting unit107 are configured individually in LTE and NR. Further, in the NR cell,some or all of the units included in the base station device 1illustrated in FIG. 8 can be configured individually in accordance witha parameter set related to the transmission signal. For example, in acertain NR cell, the wireless receiving unit 1057 and the wirelesstransmitting unit 1077 can be configured individually in accordance witha parameter set related to the transmission signal.

The higher layer processing unit 101 performs processes of a mediumaccess control (MAC) layer, a packet data convergence protocol (PDCP)layer, a radio link control (RLC) layer, and a radio resource control(RRC) layer. Further, the higher layer processing unit 101 generatescontrol information to control the receiving unit 105 and thetransmitting unit 107 and outputs the control information to the controlunit 103.

The control unit 103 controls the receiving unit 105 and thetransmitting unit 107 on the basis of the control information from thehigher layer processing unit 101. The control unit 103 generates controlinformation to be transmitted to the higher layer processing unit 101and outputs the control information to the higher layer processing unit101. The control unit 103 receives a decoded signal from the decodingunit 1051 and a channel estimation result from the channel measuringunit 1059. The control unit 103 outputs a signal to be encoded to theencoding unit 1071. Further, the control unit 103 is used to control thewhole or a part of the base station device 1.

The higher layer processing unit 101 performs a process and managementrelated to RAT control, radio resource control, sub frame setting,scheduling control, and/or CSI report control. The process and themanagement in the higher layer processing unit 101 are performed foreach terminal device or in common to terminal devices connected to thebase station device. The process and the management in the higher layerprocessing unit 101 may be performed only by the higher layer processingunit 101 or may be acquired from a higher node or another base stationdevice. Further, the process and the management in the higher layerprocessing unit 101 may be individually performed in accordance with theRAT. For example, the higher layer processing unit 101 individuallyperforms the process and the management in LTE and the process and themanagement in NR.

Under the RAT control of the higher layer processing unit 101,management related to the RAT is performed. For example, under the RATcontrol, the management related to LTE and/or the management related toNR is performed. The management related to NR includes setting and aprocess of a parameter set related to the transmission signal in the NRcell.

In the radio resource control in the higher layer processing unit 101,generation and/or management of downlink data (transport block), systeminformation, an RRC message (RRC parameter), and/or a MAC controlelement (CE) are performed.

In a sub frame setting in the higher layer processing unit 101,management of a sub frame setting, a sub frame pattern setting, anuplink-downlink setting, an uplink reference UL-DL setting, and/or adownlink reference UL-DL setting is performed. Further, the sub framesetting in the higher layer processing unit 101 is also referred to as abase station sub frame setting. Further, the sub frame setting in thehigher layer processing unit 101 can be decided on the basis of anuplink traffic volume and a downlink traffic volume. Further, the subframe setting in the higher layer processing unit 101 can be decided onthe basis of a scheduling result of scheduling control in the higherlayer processing unit 101.

In the scheduling control in the higher layer processing unit 101, afrequency and a sub frame to which the physical channel is allocated, acoding rate, a modulation scheme, and transmission power of the physicalchannels, and the like are decided on the basis of the received channelstate information, an estimation value, a channel quality, or the likeof a propagation path input from the channel measuring unit 1059, andthe like. For example, the control unit 103 generates the controlinformation (DCI format) on the basis of the scheduling result of thescheduling control in the higher layer processing unit 101.

In the CSI report control in the higher layer processing unit 101, theCSI report of the terminal device 2 is controlled. For example, asettings related to the CSI reference resources assumed to calculate theCSI in the terminal device 2 is controlled.

Under the control from the control unit 103, the receiving unit 105receives a signal transmitted from the terminal device 2 via thetransceiving antenna 109, performs a reception process such asdemultiplexing, demodulation, and decoding, and outputs informationwhich has undergone the reception process to the control unit 103.Further, the reception process in the receiving unit 105 is performed onthe basis of a setting which is specified in advance or a settingnotified from the base station device 1 to the terminal device 2.

The wireless receiving unit 1057 performs conversion into anintermediate frequency (down conversion), removal of an unnecessaryfrequency component, control of an amplification level such that asignal level is appropriately maintained, quadrature demodulation basedon an in-phase component and a quadrature component of a receivedsignal, conversion from an analog signal into a digital signal, removalof a guard interval (GI), and/or extraction of a signal in the frequencydomain by fast Fourier transform (FFT) on the uplink signal received viathe transceiving antenna 109.

The demultiplexing unit 1055 separates the uplink channel such as thePUCCH or the PUSCH and/or uplink reference signal from the signal inputfrom the wireless receiving unit 1057. The demultiplexing unit 1055outputs the uplink reference signal to the channel measuring unit 1059.The demultiplexing unit 1055 compensates the propagation path for theuplink channel from the estimation value of the propagation path inputfrom the channel measuring unit 1059.

The demodulating unit 1053 demodulates the reception signal for themodulation symbol of the uplink channel using a modulation scheme suchas binary phase shift keying (BPSK), quadrature phase shift keying(QPSK), 16 quadrature amplitude modulation (QAM), 64 QAM, or 256 QAM.The demodulating unit 1053 performs separation and demodulation of aMIMO multiplexed uplink channel.

The decoding unit 1051 performs a decoding process on encoded bits ofthe demodulated uplink channel. The decoded uplink data and/or uplinkcontrol information are output to the control unit 103. The decodingunit 1051 performs a decoding process on the PUSCH for each transportblock.

The channel measuring unit 1059 measures the estimation value, a channelquality, and/or the like of the propagation path from the uplinkreference signal input from the demultiplexing unit 1055, and outputsthe estimation value, a channel quality, and/or the like of thepropagation path to the demultiplexing unit 1055 and/or the control unit103. For example, the estimation value of the propagation path forpropagation path compensation for the PUCCH or the PUSCH is measured bythe channel measuring unit 1059 using the UL-DMRS, and an uplink channelquality is measured using the SRS.

The transmitting unit 107 carries out a transmission process such asencoding, modulation, and multiplexing on downlink control informationand downlink data input from the higher layer processing unit 101 underthe control of the control unit 103. For example, the transmitting unit107 generates and multiplexes the PHICH, the PDCCH, the EPDCCH, thePDSCH, and the downlink reference signal and generates a transmissionsignal. Further, the transmission process in the transmitting unit 107is performed on the basis of a setting which is specified in advance, asetting notified from the base station device 1 to the terminal device2, or a setting notified through the PDCCH or the EPDCCH transmittedthrough the same sub frame.

The encoding unit 1071 encodes the HARQ indicator (HARQ-ACK), thedownlink control information, and the downlink data input from thecontrol unit 103 using a predetermined coding scheme such as blockcoding, convolutional coding, turbo coding, or the like. The modulatingunit 1073 modulates the encoded bits input from the encoding unit 1071using a predetermined modulation scheme such as BPSK, QPSK, 16 QAM, 64QAM, or 256 QAM. The downlink reference signal generating unit 1079generates the downlink reference signal on the basis of a physical cellidentification (PCI), an RRC parameter set in the terminal device 2, andthe like. The multiplexing unit 1075 multiplexes a modulated symbol andthe downlink reference signal of each channel and arranges resultingdata in a predetermined resource element.

The wireless transmitting unit 1077 performs processes such asconversion into a signal in the time domain by inverse fast Fouriertransform (IFFT), addition of the guard interval, generation of abaseband digital signal, conversion in an analog signal, quadraturemodulation, conversion from a signal of an intermediate frequency into asignal of a high frequency (up conversion), removal of an extrafrequency component, and amplification of power on the signal from themultiplexing unit 1075, and generates a transmission signal. Thetransmission signal output from the wireless transmitting unit 1077 istransmitted through the transceiving antenna 109.

<Configuration Example of Base Station Device 2 in Present Embodiment>

FIG. 9 is a schematic block diagram illustrating a configuration of theterminal device 2 of the present embodiment. As illustrated, theterminal device 2 includes a higher layer processing unit 201, a controlunit 203, a receiving unit 205, a transmitting unit 207, and atransceiving antenna 209. Further, the receiving unit 205 includes adecoding unit 2051, a demodulating unit 2053, a demultiplexing unit2055, a wireless receiving unit 2057, and a channel measuring unit 2059.Further, the transmitting unit 207 includes an encoding unit 2071, amodulating unit 2073, a multiplexing unit 2075, a wireless transmittingunit 2077, and an uplink reference signal generating unit 2079.

As described above, the terminal device 2 can support one or more RATs.Some or all of the units included in the terminal device 2 illustratedin FIG. 9 can be configured individually in accordance with the RAT. Forexample, the receiving unit 205 and the transmitting unit 207 areconfigured individually in LTE and NR. Further, in the NR cell, some orall of the units included in the terminal device 2 illustrated in FIG. 9can be configured individually in accordance with a parameter setrelated to the transmission signal. For example, in a certain NR cell,the wireless receiving unit 2057 and the wireless transmitting unit 2077can be configured individually in accordance with a parameter setrelated to the transmission signal.

The higher layer processing unit 201 outputs uplink data (transportblock) to the control unit 203. The higher layer processing unit 201performs processes of a medium access control (MAC) layer, a packet dataconvergence protocol (PDCP) layer, a radio link control (RLC) layer, anda radio resource control (RRC) layer. Further, the higher layerprocessing unit 201 generates control information to control thereceiving unit 205 and the transmitting unit 207 and outputs the controlinformation to the control unit 203.

The control unit 203 controls the receiving unit 205 and thetransmitting unit 207 on the basis of the control information from thehigher layer processing unit 201. The control unit 203 generates controlinformation to be transmitted to the higher layer processing unit 201and outputs the control information to the higher layer processing unit201. The control unit 203 receives a decoded signal from the decodingunit 2051 and a channel estimation result from the channel measuringunit 2059. The control unit 203 outputs a signal to be encoded to theencoding unit 2071. Further, the control unit 203 may be used to controlthe whole or a part of the terminal device 2.

The higher layer processing unit 201 performs a process and managementrelated to RAT control, radio resource control, sub frame setting,scheduling control, and/or CSI report control. The process and themanagement in the higher layer processing unit 201 are performed on thebasis of a setting which is specified in advance and/or a setting basedon control information set or notified from the base station device 1.For example, the control information from the base station device 1includes the RRC parameter, the MAC control element, or the DCI.Further, the process and the management in the higher layer processingunit 201 may be individually performed in accordance with the RAT. Forexample, the higher layer processing unit 201 individually performs theprocess and the management in LTE and the process and the management inNR.

Under the RAT control of the higher layer processing unit 201,management related to the RAT is performed. For example, under the RATcontrol, the management related to LTE and/or the management related toNR is performed. The management related to NR includes setting and aprocess of a parameter set related to the transmission signal in the NRcell.

In the radio resource control in the higher layer processing unit 201,the setting information in the terminal device 2 is managed. In theradio resource control in the higher layer processing unit 201,generation and/or management of uplink data (transport block), systeminformation, an RRC message (RRC parameter), and/or a MAC controlelement (CE) are performed.

In the sub frame setting in the higher layer processing unit 201, thesub frame setting in the base station device 1 and/or a base stationdevice different from the base station device 1 is managed. The subframe setting includes an uplink or downlink setting for the sub frame,a sub frame pattern setting, an uplink-downlink setting, an uplinkreference UL-DL setting, and/or a downlink reference UL-DL setting.Further, the sub frame setting in the higher layer processing unit 201is also referred to as a terminal sub frame setting.

In the scheduling control in the higher layer processing unit 201,control information for controlling scheduling on the receiving unit 205and the transmitting unit 207 is generated on the basis of the DCI(scheduling information) from the base station device 1.

In the CSI report control in the higher layer processing unit 201,control related to the report of the CSI to the base station device 1 isperformed. For example, in the CSI report control, a setting related tothe CSI reference resources assumed for calculating the CSI by thechannel measuring unit 2059 is controlled. In the CSI report control,resource (timing) used for reporting the CSI is controlled on the basisof the DCI and/or the RRC parameter.

Under the control from the control unit 203, the receiving unit 205receives a signal transmitted from the base station device 1 via thetransceiving antenna 209, performs a reception process such asdemultiplexing, demodulation, and decoding, and outputs informationwhich has undergone the reception process to the control unit 203.Further, the reception process in the receiving unit 205 is performed onthe basis of a setting which is specified in advance or a notificationfrom the base station device 1 or a setting.

The wireless receiving unit 2057 performs conversion into anintermediate frequency (down conversion), removal of an unnecessaryfrequency component, control of an amplification level such that asignal level is appropriately maintained, quadrature demodulation basedon an in-phase component and a quadrature component of a receivedsignal, conversion from an analog signal into a digital signal, removalof a guard interval (GI), and/or extraction of a signal in the frequencydomain by fast Fourier transform (FFT) on the uplink signal received viathe transceiving antenna 209.

The demultiplexing unit 2055 separates the downlink channel such as thePHICH, PDCCH, EPDCCH, or PDSCH, downlink synchronization signal and/ordownlink reference signal from the signal input from the wirelessreceiving unit 2057. The demultiplexing unit 2055 outputs the uplinkreference signal to the channel measuring unit 2059. The demultiplexingunit 2055 compensates the propagation path for the uplink channel fromthe estimation value of the propagation path input from the channelmeasuring unit 2059.

The demodulating unit 2053 demodulates the reception signal for themodulation symbol of the downlink channel using a modulation scheme suchas BPSK, QPSK, 16 QAM, 64 QAM, or 256 QAM. The demodulating unit 2053performs separation and demodulation of a MIMO multiplexed downlinkchannel.

The decoding unit 2051 performs a decoding process on encoded bits ofthe demodulated downlink channel. The decoded downlink data and/ordownlink control information are output to the control unit 203. Thedecoding unit 2051 performs a decoding process on the PDSCH for eachtransport block.

The channel measuring unit 2059 measures the estimation value, a channelquality, and/or the like of the propagation path from the downlinkreference signal input from the demultiplexing unit 2055, and outputsthe estimation value, a channel quality, and/or the like of thepropagation path to the demultiplexing unit 2055 and/or the control unit203. The downlink reference signal used for measurement by the channelmeasuring unit 2059 may be decided on the basis of at least atransmission mode set by the RRC parameter and/or other RRC parameters.For example, the estimation value of the propagation path for performingthe propagation path compensation on the PDSCH or the EPDCCH is measuredthrough the DL-DMRS. The estimation value of the propagation path forperforming the propagation path compensation on the PDCCH or the PDSCHand/or the downlink channel for reporting the CSI are measured throughthe CRS. The downlink channel for reporting the CSI is measured throughthe CSI-RS. The channel measuring unit 2059 calculates a referencesignal received power (RSRP) and/or a reference signal received quality(RSRQ) on the basis of the CRS, the CSI-RS, or the discovery signal, andoutputs the RSRP and/or the RSRQ to the higher layer processing unit201.

The transmitting unit 207 performs a transmission process such asencoding, modulation, and multiplexing on the uplink control informationand the uplink data input from the higher layer processing unit 201under the control of the control unit 203. For example, the transmittingunit 207 generates and multiplexes the uplink channel such as the PUSCHor the PUCCH and/or the uplink reference signal, and generates atransmission signal. Further, the transmission process in thetransmitting unit 207 is performed on the basis of a setting which isspecified in advance or a setting set or notified from the base stationdevice 1.

The encoding unit 2071 encodes the HARQ indicator (HARQ-ACK), the uplinkcontrol information, and the uplink data input from the control unit 203using a predetermined coding scheme such as block coding, convolutionalcoding, turbo coding, or the like. The modulating unit 2073 modulatesthe encoded bits input from the encoding unit 2071 using a predeterminedmodulation scheme such as BPSK, QPSK, 16 QAM, 64 QAM, or 256 QAM. Theuplink reference signal generating unit 2079 generates the uplinkreference signal on the basis of an RRC parameter set in the terminaldevice 2, and the like. The multiplexing unit 2075 multiplexes amodulated symbol and the uplink reference signal of each channel andarranges resulting data in a predetermined resource element.

The wireless transmitting unit 2077 performs processes such asconversion into a signal in the time domain by inverse fast Fouriertransform (IFFT), addition of the guard interval, generation of abaseband digital signal, conversion in an analog signal, quadraturemodulation, conversion from a signal of an intermediate frequency into asignal of a high frequency (up conversion), removal of an extrafrequency component, and amplification of power on the signal from themultiplexing unit 2075, and generates a transmission signal. Thetransmission signal output from the wireless transmitting unit 2077 istransmitted through the transceiving antenna 209.

1.5. Control Information and Control Channel <Signaling of ControlInformation in Present Embodiment>

The base station device 1 and the terminal device 2 can use variousmethods for signaling (notification, broadcasting, or setting) of thecontrol information. The signaling of the control information can beperformed in various layers (layers). The signaling of the controlinformation includes signaling of the physical layer which is signalingperformed through the physical layer, RRC signaling which is signalingperformed through the RRC layer, and MAC signaling which is signalingperformed through the MAC layer. The RRC signaling is dedicated RRCsignaling for notifying the terminal device 2 of the control informationspecific or a common RRC signaling for notifying of the controlinformation specific to the base station device 1. The signaling used bya layer higher than the physical layer such as RRC signaling and MACsignaling is also referred to as signaling of the higher layer.

The RRC signaling is implemented by signaling the RRC parameter. The MACsignaling is implemented by signaling the MAC control element. Thesignaling of the physical layer is implemented by signaling the downlinkcontrol information (DCI) or the uplink control information (UCI). TheRRC parameter and the MAC control element are transmitted using thePDSCH or the PUSCH. The DCI is transmitted using the PDCCH or theEPDCCH. The UCI is transmitted using the PUCCH or the PUSCH. The RRCsignaling and the MAC signaling are used for signaling semi-staticcontrol information and are also referred to as semi-static signaling.The signaling of the physical layer is used for signaling dynamiccontrol information and also referred to as dynamic signaling. The DCIis used for scheduling of the PDSCH or scheduling of the PUSCH. The UCIis used for the CSI report, the HARQ-ACK report, and/or the schedulingrequest (SR).

<Details of Downlink Control Information in Present Embodiment>

The DCI is notified using the DCI format having a field which isspecified in advance. Predetermined information bits are mapped to thefield specified in the DCI format. The DCI notifies of downlinkscheduling information, uplink scheduling information, sidelinkscheduling information, a request for a non-periodic CSI report, or anuplink transmission power command.

The DCI format monitored by the terminal device 2 is decided inaccordance with the transmission mode set for each serving cell. Inother words, a part of the DCI format monitored by the terminal device 2can differ depending on the transmission mode. For example, the terminaldevice 2 in which a downlink transmission mode 1 is set monitors the DCIformat 1A and the DCI format 1. For example, the terminal device 2 inwhich a downlink transmission mode 4 is set monitors the DCI format 1Aand the DCI format 2. For example, the terminal device 2 in which anuplink transmission mode 1 is set monitors the DCI format 0. Forexample, the terminal device 2 in which an uplink transmission mode 2 isset monitors the DCI format 0 and the DCI format 4.

A control region in which the PDCCH for notifying the terminal device 2of the DCI is placed is not notified of, and the terminal device 2detects the DCI for the terminal device 2 through blind decoding (blinddetection). Specifically, the terminal device 2 monitors a set of PDCCHcandidates in the serving cell. The monitoring indicates that decodingis attempted in accordance with all the DCI formats to be monitored foreach of the PDCCHs in the set. For example, the terminal device 2attempts to decode all aggregation levels, PDCCH candidates, and DCIformats which are likely to be transmitted to the terminal device 2. Theterminal device 2 recognizes the DCI (PDCCH) which is successfullydecoded (detected) as the DCI (PDCCH) for the terminal device 2.

A cyclic redundancy check (CRC) is added to the DCI. The CRC is used forthe DCI error detection and the DCI blind detection. A CRC parity bit(CRC) is scrambled using the RNTI. The terminal device 2 detects whetheror not it is a DCI for the terminal device 2 on the basis of the RNTI.Specifically, the terminal device 2 performs de-scrambling on the bitcorresponding to the CRC using a predetermined RNTI, extracts the CRC,and detects whether or not the corresponding DCI is correct.

The RNTI is specified or set in accordance with a purpose or a use ofthe DCI. The RNTI includes a cell-RNTI (C-RNTI), a semi persistentscheduling C-RNTI (SPS C-RNTI), a system information-RNTI (SI-RNTI), apaging-RNTI (P-RNTI), a random access-RNTI (RA-RNTI), a transmit powercontrol-PUCCH-RNTI (TPC-PUCCH-RNTI), a transmit power control-PUSCH-RNTI(TPC-PUSCH-RNTI), a temporary C-RNTI, a multimedia broadcast multicastservices (MBMS)-RNTI (M-RNTI)), an eIMTA-RNTI and a CC-RNTI.

The C-RNTI and the SPS C-RNTI are RNTIs which are specific to theterminal device 2 in the base station device 1 (cell), and serve asidentifiers identifying the terminal device 2. The C-RNTI is used forscheduling the PDSCH or the PUSCH in a certain sub frame. The SPS C-RNTIis used to activate or release periodic scheduling of resources for thePDSCH or the PUSCH. A control channel having a CRC scrambled using theSI-RNTI is used for scheduling a system information block (SIB). Acontrol channel with a CRC scrambled using the P-RNTI is used forcontrolling paging. A control channel with a CRC scrambled using theRA-RNTI is used for scheduling a response to the RACH. A control channelhaving a CRC scrambled using the TPC-PUCCH-RNTI is used for powercontrol of the PUCCH. A control channel having a CRC scrambled using theTPC-PUSCH-RNTI is used for power control of the PUSCH. A control channelwith a CRC scrambled using the temporary C-RNTI is used by a mobilestation device in which no C-RNTI is set or recognized. A controlchannel with CRC scrambled using the M-RNTI is used for scheduling theMBMS. A control channel with a CRC scrambled using the eIMTA-RNTI isused for notifying of information related to a TDD UL/DL setting of aTDD serving cell in dynamic TDD (eIMTA). The control channel (DCI) witha CRC scrambled using the CC-RNTI is used to notify of setting of anexclusive OFDM symbol in the LAA secondary cell. Further, the DCI formatmay be scrambled using a new RNTI instead of the above RNTI.

Scheduling information (the downlink scheduling information, the uplinkscheduling information, and the sidelink scheduling information)includes information for scheduling in units of resource blocks orresource block groups as the scheduling of the frequency region. Theresource block group is successive resource block sets and indicatesresources allocated to the scheduled terminal device. A size of theresource block group is decided in accordance with a system bandwidth.

<Details of Downlink Control Channel in Present Embodiment>

The DCI is transmitted using a control channel such as the PDCCH or theEPDCCH. The terminal device 2 monitors a set of PDCCH candidates and/ora set of EPDCCH candidates of one or more activated serving cells set byRRC signaling. Here, the monitoring means that the PDCCH and/or theEPDCCH in the set corresponding to all the DCI formats to be monitoredis attempted to be decoded.

A set of PDCCH candidates or a set of EPDCCH candidates is also referredto as a search space. In the search space, a shared search space (CSS)and a terminal specific search space (USS) are defined. The CSS may bedefined only for the search space for the PDCCH.

A common search space (CSS) is a search space set on the basis of aparameter specific to the base station device 1 and/or a parameter whichis specified in advance. For example, the CSS is a search space used incommon to a plurality of terminal devices. Therefore, the base stationdevice 1 maps a control channel common to a plurality of terminaldevices to the CSS, and thus resources for transmitting the controlchannel are reduced.

A UE-specific search space (USS) is a search space set using at least aparameter specific to the terminal device 2. Therefore, the USS is asearch space specific to the terminal device 2, and it is possible forthe base station device 1 to individually transmit the control channelspecific to the terminal device 2 by using the USS. For this reason, thebase station device 1 can efficiently map the control channels specificto a plurality of terminal devices.

The USS may be set to be used in common to a plurality of terminaldevices. Since a common USS is set in a plurality of terminal devices, aparameter specific to the terminal device 2 is set to be the same valueamong a plurality of terminal devices. For example, a unit set to thesame parameter among a plurality of terminal devices is a cell, atransmission point, a group of predetermined terminal devices, or thelike.

The search space of each aggregation level is defined by a set of PDCCHcandidates. Each PDCCH is transmitted using one or more CCE sets. Thenumber of CCEs used in one PDCCH is also referred to as an aggregationlevel. For example, the number of CCEs used in one PDCCH is 1, 2, 4, or8.

The search space of each aggregation level is defined by a set of EPDCCHcandidates. Each EPDCCH is transmitted using one or more enhancedcontrol channel element (ECCE) sets. The number of ECCEs used in oneEPDCCH is also referred to as an aggregation level. For example, thenumber of ECCEs used in one EPDCCH is 1, 2, 4, 8, 16, or 32.

The number of PDCCH candidates or the number of EPDCCH candidates isdecided on the basis of at least the search space and the aggregationlevel. For example, in the CSS, the number of PDCCH candidates in theaggregation levels 4 and 8 are 4 and 2, respectively. For example, inthe USS, the number of PDCCH candidates in the aggregations 1, 2, 4, and8 are 6, 6, 2, and 2, respectively.

Each ECCE includes a plurality of EREGs. The EREG is used to definemapping to the resource element of the EPDCCH. 16 EREGs which areassigned numbers of 0 to 15 are defined in each RB pair. In other words,an EREG 0 to an EREG 15 are defined in each RB pair. For each RB pair,the EREG 0 to the EREG 15 are preferentially defined at regularintervals in the frequency direction for resource elements other thanresource elements to which a predetermined signal and/or channel ismapped. For example, a resource element to which a demodulationreference signal associated with an EPDCCH transmitted through antennaports 107 to 110 is mapped is not defined as the EREG.

The number of ECCEs used in one EPDCCH depends on an EPDCCH format andis decided on the basis of other parameters. The number of ECCEs used inone EPDCCH is also referred to as an aggregation level. For example, thenumber of ECCEs used in one EPDCCH is decided on the basis of the numberof resource elements which can be used for transmission of the EPDCCH inone RB pair, a transmission method of the EPDCCH, and the like. Forexample, the number of ECCEs used in one EPDCCH is 1, 2, 4, 8, 16, or32. Further, the number of EREGs used in one ECCE is decided on thebasis of a type of sub frame and a type of cyclic prefix and is 4 or 8.Distributed transmission and localized transmission are supported as thetransmission method of the EPDCCH.

The distributed transmission or the localized transmission can be usedfor the EPDCCH. The distributed transmission and the localizedtransmission differ in mapping of the ECCE to the EREG and the RB pair.For example, in the distributed transmission, one ECCE is configuredusing EREGs of a plurality of RB pairs. In the localized transmission,one ECCE is configured using an EREG of one RB pair. The base stationdevice 1 performs a setting related to the EPDCCH in the terminal device2. The terminal device 2 monitors a plurality of EPDCCHs on the basis ofthe setting from the base station device 1. A set of RB pairs that theterminal device 2 monitors the EPDCCH can be set. The set of RB pairs isalso referred to as an EPDCCH set or an EPDCCH-PRB set. One or moreEPDCCH sets can be set in one terminal device 2. Each EPDCCH setincludes one or more RB pairs. Further, the setting related to theEPDCCH can be individually performed for each EPDCCH set.

The base station device 1 can set a predetermined number of EPDCCH setsin the terminal device 2. For example, up to two EPDCCH sets can be setas an EPDCCH set 0 and/or an EPDCCH set 1. Each of the EPDCCH sets canbe constituted by a predetermined number of RB pairs. Each EPDCCH setconstitutes one set of ECCEs. The number of ECCEs configured in oneEPDCCH set is decided on the basis of the number of RB pairs set as theEPDCCH set and the number of EREGs used in one ECCE. In a case in whichthe number of ECCEs configured in one EPDCCH set is N, each EPDCCH setconstitutes ECCEs 0 to N−1. For example, in a case in which the numberof EREGs used in one ECCE is 4, the EPDCCH set constituted by 4 RB pairsconstitutes 16 ECCEs.

1.6. CA and DC <Details of CA and DC in Present Embodiment>

A plurality of cells is set for the terminal device 2, and the terminaldevice 2 can perform multicarrier transmission. Communication in whichthe terminal device 2 uses a plurality of cells is referred to ascarrier aggregation (CA) or dual connectivity (DC). Contents describedin the present embodiment can be applied to each or some of a pluralityof cells set in the terminal device 2. The cell set in the terminaldevice 2 is also referred to as a serving cell.

In the CA, a plurality of serving cells to be set includes one primarycell (PCell) and one or more secondary cells (SCell). One primary celland one or more secondary cells can be set in the terminal device 2 thatsupports the CA.

The primary cell is a serving cell in which the initial connectionestablishment procedure is performed, a serving cell that the initialconnection re-establishment procedure is started, or a cell indicated asthe primary cell in a handover procedure. The primary cell operates witha primary frequency. The secondary cell can be set after a connection isconstructed or reconstructed. The secondary cell operates with asecondary frequency. Further, the connection is also referred to as anRRC connection.

The DC is an operation in which a predetermined terminal device 2consumes radio resources provided from at least two different networkpoints. The network point is a master base station device (a master eNB(MeNB)) and a secondary base station device (a secondary eNB (SeNB)). Inthe dual connectivity, the terminal device 2 establishes an RRCconnection through at least two network points. In the dualconnectivity, the two network points may be connected through anon-ideal backhaul.

In the DC, the base station device 1 which is connected to at least anS1-MME and plays a role of a mobility anchor of a core network isreferred to as a master base station device. Further, the base stationdevice 1 which is not the master base station device providingadditional radio resources to the terminal device 2 is referred to as asecondary base station device. A group of serving cells associated withthe master base station device is also referred to as a master cellgroup (MCG). A group of serving cells associated with the secondary basestation device is also referred to as a secondary cell group (SCG). Notethat the group of the serving cells is also referred to as a cell group(CG).

In the DC, the primary cell belongs to the MCG. Further, in the SCG, thesecondary cell corresponding to the primary cell is referred to as aprimary secondary cell (PSCell). A function (capability and performance)equivalent to the PCell (the base station device constituting the PCell)may be supported by the PSCell (the base station device constituting thePSCell). Further, the PSCell may only support some functions of thePCell. For example, the PSCell may support a function of performing thePDCCH transmission using the search space different from the CSS or theUSS. Further, the PSCell may constantly be in an activation state.Further, the PSCell is a cell that can receive the PUCCH.

In the DC, a radio bearer (a date radio bearer (DRB)) and/or a signalingradio bearer (SRB) may be individually allocated through the MeNB andthe SeNB. A duplex mode may be set individually in each of the MCG(PCell) and the SCG (PSCell). The MCG (PCell) and the SCG (PSCell) maynot be synchronized with each other. That is, a frame boundary of theMCG and a frame boundary of the SCG may not be matched. A parameter (atiming advance group (TAG)) for adjusting a plurality of timings may beindependently set in the MCG (PCell) and the SCG (PSCell). In the dualconnectivity, the terminal device 2 transmits the UCI corresponding tothe cell in the MCG only through MeNB (PCell) and transmits the UCIcorresponding to the cell in the SCG only through SeNB (pSCell). In thetransmission of each UCI, the transmission method using the PUCCH and/orthe PUSCH is applied in each cell group.

The PUCCH and the PBCH (MIB) are transmitted only through the PCell orthe PSCell. Further, the PRACH is transmitted only through the PCell orthe PSCell as long as a plurality of TAGs is not set between cells inthe CG.

In the PCell or the PSCell, semi-persistent scheduling (SPS) ordiscontinuous transmission (DRX) may be performed. In the secondarycell, the same DRX as the PCell or the PSCell in the same cell group maybe performed.

In the secondary cell, information/parameter related to a setting of MACis basically shared with the PCell or the PSCell in the same cell group.Some parameters may be set for each secondary cell. Some timers orcounters may be applied only to the PCell or the PSCell.

In the CA, a cell to which the TDD scheme is applied and a cell to whichthe FDD scheme is applied may be aggregated. In a case in which the cellto which the TDD is applied and the cell to which the FDD is applied areaggregated, the present disclosure can be applied to either the cell towhich the TDD is applied or the cell to which the FDD is applied.

The terminal device 2 transmits information (supportedBandCombination)indicating a combination of bands in which the CA and/or DC is supportedby the terminal device 2 to the base station device 1. The terminaldevice 2 transmits information indicating whether or not simultaneoustransmission and reception are supported in a plurality of serving cellsin a plurality of different bands for each of band combinations to thebase station device 1.

1.7. Resource Allocation <Details of Resource Allocation in PresentEmbodiment>

The base station device 1 can use a plurality of methods as a method ofallocating resources of the PDSCH and/or the PUSCH to the terminaldevice 2. The resource allocation method includes dynamic scheduling,semi persistent scheduling, multi sub frame scheduling, and cross subframe scheduling.

In the dynamic scheduling, one DCI performs resource allocation in onesub frame. Specifically, the PDCCH or the EPDCCH in a certain sub frameperforms scheduling for the PDSCH in the sub frame. The PDCCH or theEPDCCH in a certain sub frame performs scheduling for the PUSCH in apredetermined sub frame after the certain sub frame.

In the multi sub frame scheduling, one DCI allocates resources in one ormore sub frames. Specifically, the PDCCH or the EPDCCH in a certain subframe performs scheduling for the PDSCH in one or more sub frames whichare a predetermined number after the certain sub frame. The PDCCH or theEPDCCH in a certain sub frame performs scheduling for the PUSCH in oneor more sub frames which are a predetermined number after the sub frame.The predetermined number can be set to an integer of zero or more. Thepredetermined number may be specified in advance and may be decided onthe basis of the signaling of the physical layer and/or the RRCsignaling. In the multi sub frame scheduling, consecutive sub frames maybe scheduled, or sub frames with a predetermined period may bescheduled. The number of sub frames to be scheduled may be specified inadvance or may be decided on the basis of the signaling of the physicallayer and/or the RRC signaling.

In the cross sub frame scheduling, one DCI allocates resources in onesub frame. Specifically, the PDCCH or the EPDCCH in a certain sub frameperforms scheduling for the PDSCH in one sub frame which is apredetermined number after the certain sub frame. The PDCCH or theEPDCCH in a certain sub frame performs scheduling for the PUSCH in onesub frame which is a predetermined number after the sub frame. Thepredetermined number can be set to an integer of zero or more. Thepredetermined number may be specified in advance and may be decided onthe basis of the signaling of the physical layer and/or the RRCsignaling. In the cross sub frame scheduling, consecutive sub frames maybe scheduled, or sub frames with a predetermined period may bescheduled.

In the semi-persistent scheduling (SPS), one DCI allocates resources inone or more sub frames. In a case in which information related to theSPS is set through the RRC signaling, and the PDCCH or the EPDCCH foractivating the SPS is detected, the terminal device 2 activates aprocess related to the SPS and receives a predetermined PDSCH and/orPUSCH on the basis of a setting related to the SPS. In a case in whichthe PDCCH or the EPDCCH for releasing the SPS is detected when the SPSis activated, the terminal device 2 releases (inactivates) the SPS andstops reception of a predetermined PDSCH and/or PUSCH. The release ofthe SPS may be performed on the basis of a case in which a predeterminedcondition is satisfied. For example, in a case in which a predeterminednumber of empty transmission data is received, the SPS is released. Thedata empty transmission for releasing the SPS corresponds to a MACprotocol data unit (PDU) including a zero MAC service data unit (SDU).

Information related to the SPS by the RRC signaling includes an SPSC-RNTI which is an SPN RNTI, information related to a period (interval)in which the PDSCH is scheduled, information related to a period(interval) in which the PUSCH is scheduled, information related to asetting for releasing the SPS, and/or the number of the HARQ process inthe SPS. The SPS is supported only in the primary cell and/or theprimary secondary cell.

1.8. Error Correction <HARQ in Present Embodiment>

In the present embodiment, the HARQ has various features. The HARQtransmits and retransmits the transport block. In the HARQ, apredetermined number of processes (HARQ processes) are used (set), andeach process independently operates in accordance with a stop-and-waitscheme.

In the downlink, the HARQ is asynchronous and operates adaptively. Inother words, in the downlink, retransmission is constantly scheduledthrough the PDCCH. The uplink HARQ-ACK (response information)corresponding to the downlink transmission is transmitted through thePUCCH or the PUSCH. In the downlink, the PDCCH notifies of a HARQprocess number indicating the HARQ process and information indicatingwhether or not transmission is initial transmission or retransmission.

In the uplink, the HARQ operates in a synchronous or asynchronousmanner. The downlink HARQ-ACK (response information) corresponding tothe uplink transmission is transmitted through the PHICH. In the uplinkHARQ, an operation of the terminal device is decided on the basis of theHARQ feedback received by the terminal device and/or the PDCCH receivedby the terminal device. For example, in a case in which the PDCCH is notreceived, and the HARQ feedback is ACK, the terminal device does notperform transmission (retransmission) but holds data in a HARQ buffer.In this case, the PDCCH may be transmitted in order to resume theretransmission. Further, for example, in a case in which the PDCCH isnot received, and the HARQ feedback is NACK, the terminal deviceperforms retransmission non-adaptively through a predetermined uplinksub frame. Further, for example, in a case in which the PDCCH isreceived, the terminal device performs transmission or retransmission onthe basis of contents notified through the PDCCH regardless of contentof the HARQ feedback.

Further, in the uplink, in a case in which a predetermined condition(setting) is satisfied, the HARQ may be operated only in an asynchronousmanner. In other words, the downlink HARQ-ACK is not transmitted, andthe uplink retransmission may constantly be scheduled through the PDCCH.

In the HARQ-ACK report, the HARQ-ACK indicates ACK, NACK, or DTX. In acase in which the HARQ-ACK is ACK, it indicates that the transport block(codeword and channel) corresponding to the HARQ-ACK is correctlyreceived (decoded). In a case in which the HARQ-ACK is NACK, itindicates that the transport block (codeword and channel) correspondingto the HARQ-ACK is not correctly received (decoded). In a case in whichthe HARQ-ACK is DTX, it indicates that the transport block (codeword andchannel) corresponding to the HARQ-ACK is not present (not transmitted).

A predetermined number of HARQ processes are set (specified) in each ofdownlink and uplink. For example, in FDD, up to eight HARQ processes areused for each serving cell. Further, for example, in TDD, a maximumnumber of HARQ processes is decided by an uplink/downlink setting. Amaximum number of HARQ processes may be decided on the basis of a roundtrip time (RTT). For example, in a case in which the RTT is 8 TTIs, themaximum number of the HARQ processes can be 8.

In the present embodiment, the HARQ information is constituted by atleast a new data indicator (NDI) and a transport block size (TBS). TheNDI is information indicating whether or not the transport blockcorresponding to the HARQ information is initial transmission orretransmission. The TBS is the size of the transport block. Thetransport block is a block of data in a transport channel (transportlayer) and can be a unit for performing the HARQ. In the DL-SCHtransmission, the HARQ information further includes a HARQ process ID (aHARQ process number). In the UL-SCH transmission, the HARQ informationfurther includes an information bit in which the transport block isencoded and a redundancy version (RV) which is information specifying aparity bit. In the case of spatial multiplexing in the DL-SCH, the HARQinformation thereof includes a set of NDI and TBS for each transportblock.

1.9. Resource Element Mapping <Details of LTE Downlink Resource ElementMapping in Present Embodiment>

FIG. 10 is a diagram illustrating an example of LTE downlink resourceelement mapping in the present embodiment. In this example, a set ofresource elements in one resource block pair in a case in which oneresource block and the number of OFDM symbols in one slot are 7 will bedescribed. Further, seven OFDM symbols in a first half in the timedirection in the resource block pair are also referred to as a slot 0 (afirst slot). Seven OFDM symbols in a second half in the time directionin the resource block pair are also referred to as a slot 1 (a secondslot). Further, the OFDM symbols in each slot (resource block) areindicated by OFDM symbol number 0 to 6. Further, the sub carriers in thefrequency direction in the resource block pair are indicated by subcarrier numbers 0 to 11. Further, in a case in which a system bandwidthis constituted by a plurality of resource blocks, a different subcarrier number is allocated over the system bandwidth. For example, in acase in which the system bandwidth is constituted by six resourceblocks, the sub carriers to which the sub carrier numbers 0 to 71 areallocated are used. Further, in the description of the presentembodiment, a resource element (k, 1) is a resource element indicated bya sub carrier number k and an OFDM symbol number 1.

Resource elements indicated by R 0 to R 3 indicate cell-specificreference signals of the antenna ports 0 to 3, respectively.Hereinafter, the cell-specific reference signals of the antenna ports 0to 3 are also referred to as cell-specific RSs (CRSs). In this example,the case of the antenna ports in which the number of CRSs is 4 isdescribed, but the number thereof can be changed. For example, the CRScan use one antenna port or two antenna ports. Further, the CRS canshift in the frequency direction on the basis of the cell ID. Forexample, the CRS can shift in the frequency direction on the basis of aremainder obtained by dividing the cell ID by 6.

Resource element indicated by C1 to C4 indicates reference signals(CSI-RS) for measuring transmission path states of the antenna ports 15to 22. The resource elements denoted by C1 to C4 indicate CSI-RSs of aCDM group 1 to a CDM group 4, respectively. The CSI-RS is constituted byan orthogonal sequence (orthogonal code) using a Walsh code and ascramble code using a pseudo random sequence. Further, the CSI-RS iscode division multiplexed using an orthogonal code such as a Walsh codein the CDM group. Further, the CSI-RS is frequency-division multiplexed(FDM) mutually between the CDM groups.

The CSI-RSs of the antenna ports 15 and 16 are mapped to C1. The CSI-RSsof the antenna ports 17 and 18 is mapped to C2. The CSI-RSs of theantenna port 19 and 20 are mapped to C3. The CSI-RSs of the antenna port21 and 22 are mapped to C4.

A plurality of antenna ports of the CSI-RSs is specified. The CSI-RS canbe set as a reference signal corresponding to eight antenna ports of theantenna ports 15 to 22. Further, the CSI-RS can be set as a referencesignal corresponding to four antenna ports of the antenna ports 15 to18. Further, the CSI-RS can be set as a reference signal correspondingto two antenna ports of the antenna ports 15 to 16. Further, the CSI-RScan be set as a reference signal corresponding to one antenna port ofthe antenna port 15. The CSI-RS can be mapped to some sub frames, and,for example, the CSI-RS can be mapped for every two or more sub frames.A plurality of mapping patterns is specified for the resource element ofthe CSI-RS. Further, the base station device 1 can set a plurality ofCSI-RSs in the terminal device 2.

The CSI-RS can set transmission power to zero. The CSI-RS with zerotransmission power is also referred to as a zero power CSI-RS. The zeropower CSI-RS is set independently of the CSI-RS of the antenna ports 15to 22. Further, the CSI-RS of the antenna ports 15 to 22 is alsoreferred to as a non-zero power CSI-RS.

The base station device 1 sets CSI-RS as control information specific tothe terminal device 2 through the RRC signaling. In the terminal device2, the CSI-RS is set through the RRC signaling by the base stationdevice 1. Further, in the terminal device 2, the CSI-IM resources whichare resources for measuring interference power can be set. The terminaldevice 2 generates feedback information using the CRS, the CSI-RS,and/or the CSI-IM resources on the basis of a setting from the basestation device 1.

Resource elements indicated by D1 to D2 indicate the DL-DMRSs of the CDMgroup 1 and the CDM group 2, respectively. The DL-DMRS is constitutedusing an orthogonal sequence (orthogonal code) using a Walsh code and ascramble sequence according to a pseudo random sequence. Further, theDL-DMRS is independent for each antenna port and can be multiplexedwithin each resource block pair. The DL-DMRSs are in an orthogonalrelation with each other between the antenna ports in accordance withthe CDM and/or the FDM. Each of DL-DMRSs undergoes the CDM in the CDMgroup in accordance with the orthogonal codes. The DL-DMRSs undergo theFDM with each other between the CDM groups. The DL-DMRSs in the same CDMgroup are mapped to the same resource element. For the DL-DMRSs in thesame CDM group, different orthogonal sequences are used between theantenna ports, and the orthogonal sequences are in the orthogonalrelation with each other. The DL-DMRS for the PDSCH can use some or allof the eight antenna ports (the antenna ports 7 to 14). In other words,the PDSCH associated with the DL-DMRS can perform MIMO transmission ofup to 8 ranks. The DL-DMRS for the EPDCCH can use some or all of thefour antenna ports (the antenna ports 107 to 110). Further, the DL-DMRScan change a spreading code length of the CDM or the number of resourceelements to be mapped in accordance with the number of ranks of anassociated channel.

The DL-DMRS for the PDSCH to be transmitted through the antenna ports 7,8, 11, and 13 are mapped to the resource element indicated by D1. TheDL-DMRS for the PDSCH to be transmitted through the antenna ports 9, 10,12, and 14 are mapped to the resource element indicated by D2. Further,the DL-DMRS for the EPDCCH to be transmitted through the antenna ports107 and 108 are mapped to the resource element indicated by D1. TheDL-DMRS for the EPDCCH to be transmitted through the antenna ports 109and 110 are mapped to the resource element denoted by D2.

<Details of Downlink Resource Elements Mapping of NR in PresentEmbodiment>

FIG. 11 is a diagram illustrating an example of the downlink resourceelement mapping of NR according to the present embodiment. FIG. 11illustrates a set of resource elements in the predetermined resources ina case in which parameter set 0 is used. The predetermined resourcesillustrated in FIG. 11 are resources formed by a time length and afrequency bandwidth such as one resource block pair in LTE.

In NR, the predetermined resource is referred to as an NR resource block(NR-RB). The predetermined resource can be used for a unit of allocationof the NR-PDSCH or the NR-PDCCH, a unit in which mapping of thepredetermined channel or the predetermined signal to a resource elementis defined, or a unit in which the parameter set is set.

In the example of FIG. 11 , the predetermined resources include 14 OFDMsymbols indicated by OFDM symbol numbers 0 to 13 in the time directionand 12 sub carriers indicated by sub carrier numbers 0 to 11 in thefrequency direction. In a case in which the system bandwidth includesthe plurality of predetermined resources, sub carrier numbers areallocated throughout the system bandwidth.

Resource elements indicated by C1 to C4 indicate reference signals(CSI-RS) for measuring transmission path states of the antenna ports 15to 22. Resource elements indicated by D1 and D2 indicate DL-DMRS of CDMgroup 1 and CDM group 2, respectively.

FIG. 12 is a diagram illustrating an example of the downlink resourceelement mapping of NR according to the present embodiment. FIG. 12illustrates a set of resource elements in the predetermined resources ina case in which parameter set 1 is used. The predetermined resourcesillustrated in FIG. 12 are resources formed by the same time length andfrequency bandwidth as one resource block pair in LTE.

In the example of FIG. 12 , the predetermined resources include 7 OFDMsymbols indicated by OFDM symbol numbers 0 to 6 in the time directionand 24 sub carriers indicated by sub carrier numbers 0 to 23 in thefrequency direction. In a case in which the system bandwidth includesthe plurality of predetermined resources, sub carrier numbers areallocated throughout the system bandwidth.

Resource elements indicated by C1 to C4 indicate reference signals(CSI-RS) for measuring transmission path states of the antenna ports 15to 22. Resource elements indicated by D1 and D2 indicate DL-DMRS of CDMgroup 1 and CDM group 2, respectively.

FIG. 15 is a diagram illustrating an example of the downlink resourceelement mapping of NR according to the present embodiment. FIG. 15illustrates a set of resource elements in the predetermined resources ina case in which parameter set 1 is used. The predetermined resourcesillustrated in FIG. 15 are resources formed by the same time length andfrequency bandwidth as one resource block pair in LTE.

In the example of FIG. 13 , the predetermined resources include 28 OFDMsymbols indicated by OFDM symbol numbers 0 to 27 in the time directionand 6 sub carriers indicated by sub carrier numbers 0 to 6 in thefrequency direction. In a case in which the system bandwidth includesthe plurality of predetermined resources, sub carrier numbers areallocated throughout the system bandwidth.

Resource elements indicated by C1 to C4 indicate reference signals(CSI-RS) for measuring transmission path states of the antenna ports 15to 22. Resource elements indicated by D1 and D2 indicate DL-DMRS of CDMgroup 1 and CDM group 2, respectively.

1.10. Self-Contained Transmission <Details of Self-ContainedTransmission of NR in Present Embodiment>

In NR, a physical channel and/or a physical signal can be transmitted byself-contained transmission. FIG. 14 illustrates an example of a frameconfiguration of the self-contained transmission in the presentembodiment. In the self-contained transmission, single transceivingincludes successive downlink transmission, a GP, and successive downlinktransmission from the head in this order. The successive downlinktransmission includes at least one piece of downlink control informationand the DMRS. The downlink control information gives an instruction toreceive a downlink physical channel included in the successive downlinktransmission and to transmit an uplink physical channel included in thesuccessive uplink transmission. In a case in which the downlink controlinformation gives an instruction to receive the downlink physicalchannel, the terminal device 2 attempts to receive the downlink physicalchannel on the basis of the downlink control information. Then, theterminal device 2 transmits success or failure of reception of thedownlink physical channel (decoding success or failure) by an uplinkcontrol channel included in the uplink transmission allocated after theGP. On the other hand, in a case in which the downlink controlinformation gives an instruction to transmit the uplink physicalchannel, the uplink physical channel transmitted on the basis of thedownlink control information is included in the uplink transmission tobe transmitted. In this way, by flexibly switching between transmissionof uplink data and transmission of downlink data by the downlink controlinformation, it is possible to take countermeasures instantaneously toincrease or decrease a traffic ratio between an uplink and a downlink.Further, by notifying of the success or failure of the reception of thedownlink by the uplink transmission immediately after the success orfailure of reception of the downlink, it is possible to realizelow-delay communication of the downlink.

A unit slot time is a minimum time unit in which downlink transmission,a GP, or uplink transmission is defined. The unit slot time is reservedfor one of the downlink transmission, the GP, and the uplinktransmission. In the unit slot time, neither the downlink transmissionnor the uplink transmission is included. The unit slot time may be aminimum transmission time of a channel associated with the DMRS includedin the unit slot time. One unit slot time is defined as, for example, aninteger multiple of a sampling interval (T_(s)) or the symbol length ofNR.

The unit frame time may be a minimum time designated by scheduling. Theunit frame time may be a minimum unit in which a transport block istransmitted. The unit slot time may be a maximum transmission time of achannel associated with the DMRS included in the unit slot time. Theunit frame time may be a unit time in which the uplink transmissionpower in the terminal device 2 is decided. The unit frame time may bereferred to as a sub frame. In the unit frame time, there are threetypes of only the downlink transmission, only the uplink transmission,and a combination of the uplink transmission and the downlinktransmission. One unit frame time is defined as, for example, an integermultiple of the sampling interval (T_(s)), the symbol length, or theunit slot time of NR.

A transceiving time is one transceiving time. A time (a gap) in whichneither the physical channel nor the physical signal is transmitted mayoccupy between one transceiving and another transceiving. The terminaldevice 2 may not average the CSI measurement between differenttransceiving. The transceiving time may be referred to as TTI. Onetransceiving time is defined as, for example, an integer multiple of thesampling interval (TO, the symbol length, the unit slot time, or theunit frame time of NR.

1.11. Technical Features <Details of LAA in Present Embodiment>

First, LAA will be described. The terminal device acquires informationregarding an occupied OFDM symbol configuration on the basis of the DCIof a PDCCH to which a CRC scrambled with a CC-RNTI transmitted in an LAAsecondary cell is added. The CC-RNTI is a common RNTI of the terminaldevices for identifying the PDCCH including the information regarding ofthe occupied OFDM symbol configuration. The information regarding theoccupied OFDM symbol configuration is 4-bit information indicating anoccupied (transmitted) final OFDM symbol in a sub frame in which the DCIis detected and a subsequent sub frame. The information regarding theoccupied OFDM symbol configuration enables the terminal device torecognize up to which OFDM symbol is scheduled to be transmitted in thesub frame in which the DCI is detected and the subsequent sub frame.Simultaneously, the terminal device can recognize up to which CRS isscheduled to be transmitted in the sub frame in which the DCI isdetected and the subsequent sub frame. Note that the occupied OFDM is anOFDM used to transmit a physical channel and/or a physical signal.

<Details of Radio Link Monitoring (RLM) in Present Embodiment>

Next, the details of the radio link monitoring (RLM) will be described.The RLM is used to maintain stability of connection establishmentbetween a base station device (EUTRA) and a terminal device (UE) inexchange of information regarding a higher layer such as the RRC layer.The RLM enables the terminal device to determine whether downlinkconnection is stably maintained.

Specifically, the terminal device detects quality of connection (link)with the base station device (a cell or a serving cell) to which theterminal device is connected and monitors downlink quality of a primarycell in order to instruct the higher layer of an in-synchronization(in-sync) state or an out-of-synchronization (out-of-sync) state. Inaddition, in a case in which dual connectivity (SCG) is set and aparameter related to a radio link failure (RLF) is supplied from thehigher layer, the terminal device monitors downlink quality of a primarysecondary cell. Hereinafter, monitoring of the downlink quality is alsoreferred to as RLM measurement. Note that the in-synchronization(in-sync) state may also be regarded as a state in which the terminaldevice is inside coverage (in-coverage) of a measured cell. In addition,the out-of-synchronization (out-of-sync) state may also be regarded as astate in which the terminal device is out of the coverage(out-of-coverage) of the measured cell.

The downlink quality (that is, a downlink radio link quality or downlinklink quality) is monitored on the basis of a synchronization signal or areference signal which is a known signal between the base station andthe terminal device. As a specific example, the downlink quality ismonitored on the basis of cell-specific reference signal (CRS). Inaddition, as another specific example, the downlink quality may also bemonitored on the basis of a CSI-RS. In addition, as another example, thedownlink quality may be monitored on the basis of the PRS. In addition,as still another example, the downlink quality may be monitored on thebasis of a demodulation reference signal (DMRS). In addition, as stillanother example, the downlink quality may be monitored on the basis of aprimary synchronization signal (PSS) and/or a secondary synchronizationsignal (SSS). In addition, as still another specific example, thedownlink quality may be monitored on the basis of a discovery signal. Inaddition, for example, the downlink quality is defined with receptionpower of a synchronization signal and/or a reference signal transmittedfrom a serving cell. In addition, for example, the downlink quality maybe defined with a value of an RSRP or an RSRQ from the serving cell.

Note that a frequency band for measuring the downlink quality ispreferably a system band of the serving cell of which the downlinkquality is measured, but may be another bandwidth. Examples of thebandwidth for measuring the downlink quality include a PRB in which anEPDDCH is set, a band in which a downlink control channel which can becommonly received between the terminal devices is disposed, a band of aminimum bandwidth which can be received by the terminal device, a bandin which the PSS/SSS is disposed, and a band in which the PBCH isdisposed.

Whether the radio link quality indicates in-synchronization (in-sync) orout-of-synchronization (out-of-sync) is evaluated by comparing thedownlink radio link quality to a threshold. As the threshold, athreshold Q_(in) used to determine in-synchronization (in-sync) and athreshold Q_(out) used to determine out-of-synchronization (out-of-sync)are decided.

For example, FIG. 15 is an explanatory diagram illustrating examples ofa time variation of radio link quality and each of an in-synchronizationstate and an out-of-synchronization state. The example illustrated inFIG. 15 is an example of a case in which the in-synchronization(in-sync) state transitions to the out-of-synchronization (out-of-sync)state. Specifically, in a case in which the radio link quality islowered to be less than the threshold Q_(out), the physical layer of theterminal device broadcasts the out-of-synchronization (out-of-sync)state to the higher layer. In addition, in a subsequent evaluationtiming, in a case in which the radio link quality is not greater thanthe threshold Q_(in), the physical layer of the terminal devicebroadcasts the out-of-synchronization (out-of-sync) state to the higherlayer. In a case in which the out-of-synchronization (out-of-sync) isbroadcast consecutively a predetermined number of times (N310 or N313)set with the parameter related to the radio link failure (RLF), thehigher layer determines that there is a problem in the physical layerand causes an RLF timer (T310 or T313) to start. In a case in which thein-synchronization (in-sync) is broadcast consecutively a predeterminednumber of times (N311 or N314) set with the parameter related to the RLFbefore the RLF timer expires, the higher layer determines that theproblem in the physical layer is resolved and causes the RLF timer (T310or T313) to stop. Conversely, in a case in which the RLF timer expires,the RLF occurs and the terminal device performs separation from an RRCconnection (RRC CONNECTED) mode or connection reestablishment. Inaddition, in a case in which the RLF timer (T310) of the primary cellexpires, transmission power of the terminal device is cut off within 40ms. In addition, in a case in which the RLF timer (T313) of the primarysecondary cell expires, transmission power of the primary secondary cellis cut off within 40 ms.

The threshold Q_(out) and the threshold Q_(in) are defined at a level atwhich an environment in which information regarding the higher layersuch as the RRC layer can be exchanged stably between the base stationdevice and the terminal device is assumed. For example, the level isdefined with an error ratio of a channel necessary to send theinformation regarding the higher layer. For example, the thresholdQ_(out) is defined at a level equivalent to 10% of a block error rate ofvirtual PDCCH transmission in which a PCFICH error is considered. As thevirtual PDCCH, a PDCCH transmitted with a DCI format 1A, an aggregationlevel of 4 or 8, and a boost of 1 dB or 4 dB from average RS power isassumed. In addition, for example, the threshold Q_(in) is defined at alevel sufficiently better than the threshold Q_(out) in the receptionquality and equivalent to 2% of the block error rate of virtual PDCCHtransmission in which the PCFICH error is considered. As the virtualPDCCH, a PDCCH transmitted with a DCI format 1C, an aggregation level of4, and a boost of 1 dB or 4 dB from the average RS power is assumed.Note that, in a case in which the downlink quality is defined withreception power of the reference signal and the synchronization signal,the threshold Q_(in) and the threshold Q_(out) are defined as powervalues equivalent to the levels of the foregoing examples. In a case inwhich the downlink quality is defined with RSRP or RSRQ, the thresholdQ_(in) and the threshold Q_(out) are defined with values of RSRP or RSRQequivalent to the foregoing levels. Note that the threshold Q_(in) andthe threshold Q_(out) are preferably values of different levels.Specifically, the threshold Q_(in) is preferably a value higher than thethreshold Q_(out).

The terminal device may measure radio link quality of all the wirelessframes in a predetermined time section. In addition, in a case in whicha discontinuous reception (DRX) mode is set, the terminal device maymeasure radio link quality of an entire DRX section in a predeterminedtime section.

As predetermined time sections in which the terminal device evaluatesthe radio link quality, a time section T_(Evaluate)_Q_(in) forevaluating in-synchronization (in-sync) and a time sectionT_(Evaluate)_Q_(out) for evaluating out-of-synchronization (out-of-sync)are each individually defined.

The time section T_(Evaluate)_Q_(out) is a minimum measurement sectiondefined to evaluate the out-of-synchronization (out-of-sync). Forexample, a predetermined period (for example, 200 ms), a length of a DRXcycle, or the like can be set. Note that the foregoing example is aminimum section and the terminal device may perform measurement over aperiod longer than the foregoing example.

The time section T_(Evaluate)_Q_(in) is a minimum measurement sectiondefined to evaluate the in-synchronization (in-sync). For example, apredetermined period (for example, 100 ms), a length of the DRX cycle,or the like can be set. Note that the foregoing example is a minimumsection and the terminal device may perform measurement over a periodlonger than the foregoing example.

As broadcast periods of the in-synchronization (in-sync) and theout-of-synchronization (out-of-sync), 10 ms (one wireless frame) may beset at minimum.

<Synchronization in LAA in Present Embodiment>

Next, synchronization in LAA will be described. In a known LAAtechnology, a cell (carrier) operated in the unlicensed band is limitedto only an operation as a secondary cell. In addition, in this case, inthe LAA secondary cell, stability of connection with the LAA secondarycell may not be guaranteed since assistance with information necessaryfor connection from the primary cell operated in the licensed band ispossible. On the other hand, in order to further extend flexibility ofthe operation, the operation as the primary cell or the primarysecondary cell is also preferable in the cell (the carrier) operated inthe unlicensed band. In this case, it is assumed that it is difficult toobtain assistance information from the serving cell operated in thelicensed band or the obtained assistance information is insufficient.Therefore, on the assumption of such a situation, the stability ofconnection is ensured by performing the RLM even in LAA in the systemaccording to the present embodiment.

<RLM of LAA in Present Embodiment>

Next, the RLM in LAA will be described. In the system according to thepresent embodiment, for example, the CRS is used to measure downlinkradio link quality. On the other hand, in the unlicensed band, the CRSis not necessarily transmitted consecutively (continuously) forcoexistence of different nodes or different systems. In other words, inthe unlicensed band, a predetermined reference signal used to measurecommunication quality as in the CRS can be selectively transmitted in atleast some of the sub frames. That is, in the unlicensed band, thereference signal such as the CRS is not transmitted during all the unitperiods such as the sub frames, and the reference signal is nottransmitted during some of the unit periods in some cases. Therefore, inLAA in which an operation in the unlicensed band is assumed, the CRS isdiscontinuously transmitted.

For example, FIG. 16 is an explanatory diagram illustrating an exampleof transmission of a reference signal (RS) used to measure downlinkradio link quality. An example illustrated in (a) of FIG. 16 is atransmission example of the RS in a case in which LTE is operated in thelicensed band. In addition, an example illustrated in (b) of FIG. 16 isa transmission example of the RS in a case in which LTE is operated inthe unlicensed band. In the example illustrated in (a) of FIG. 16 , thebase station device can consecutively transmit the CRS or the DS. Thatis, in this case, the terminal device can perform RLM measurement on theassumption that the CRS or the DS is consecutively transmitted. On theother hand, in the example illustrated in (b) of FIG. 16 , the basestation device determines whether or not to transmit the CRS or the DSon the basis of a result of channel sensing by Listen Before Talk (LBT)before the transmission is performed. Further, in the unlicensed band,the base station device ends the transmission within a predeterminedsection. Therefore, in the unlicensed band, a section in which both theDS and the CRS are not transmitted (that is, the unit period such as thesub frame) can occur as in the example illustrated in (b) of FIG. 16 .

Here, when a section in which the CRS is not transmitted is added to anevaluation target of the downlink quality in the RLM measurement, theterminal device can broadcast the out-of-synchronization (out-of-sync)at a high frequency. Therefore, in this case, it is preferable toexclude the section in which the CRS is not transmitted as an evaluationtarget. Accordingly, hereinafter, an example of a technique by which thesection in which the CRS is not transmitted can be excluded as anevaluation target of the communication quality will be described as anexample of a technique for the RLM measurement in LAA.

For example, as an example of the technique for the RLM measurement inLAA, a technique for performing the RLM measurement in a sub frame (unitperiod) with which the DS is transmitted in a section set as a discoverymeasurement timing configuration (DMTC) can be exemplified. The DMTC isset with an RRC message in the terminal device. Note that the DMTC maybe broadcast with broadcast information (for example, an MIB or an SIB)in a case in which initial connection of LTE in the unlicensed band isperformed. In a case in which the sub frame with which the DS istransmitted is detected in one sub frame in the DMTC section, the onesub frame is used to evaluate the radio link quality and five other subframes are not used to evaluate the radio link quality. Here, the subframe in which the DS is transmitted is equivalent to, for example, asub frame in which the PSS and the SSS are transmitted. That is, thecase in which the sub frame with which the DS is transmitted is detectedis equivalent to a case in which the PSS and the SSS are detected.Specifically, in a case in which the PSS and the SSS are detected, theterminal device performs the RLM measurement by measuring receptionpower of the CRS in the sub frame in which the PSS and the SSS aredetected. That is, in this case, evaluation based on the RLM measurementis performed with only a target sub frame within a predetermined time.As a more specific example, communication quality is measured with onlya valid sub frame during a predetermined period (for example, 100 ms).

In addition, as another example of the technique for the RLM measurementin LAA, a technique for performing the RLM measurement on the basis of aspecific downlink period instructed with the PDCCH can be exemplified.For example, the RLM measurement may be performed on the basis of a subframe (unit period) and an OFDM symbol for which a transmission scheduleis instructed with information regarding an occupied OFDM symbolconfiguration. Specifically, the terminal device estimates an OFDM withwhich the CRS is transmitted from information regarding an OFDM symbolscheduled to be transmitted in the sub frame or a subsequent sub framerather than the information regarding the occupied OFDM symbolconfiguration and performs the RLM measurement using the OFDM.

In addition, as still another example of the technique for the RLMmeasurement in LAA, the RLM measurement may be performed even in a subframe (unit period) instructed with the occupied OFDM symbolconfiguration in addition to the sub frame (the unit period) with whichthe DS in the section set as a discovery measurement timingconfiguration (DMTC) is transmitted.

In addition, as still another example of the technique for the RLMmeasurement in LAA, the RLM measurement may be performed with a subframe (unit period) in which a synchronization signal (PSS/SSS) istransmitted. As a specific example, the terminal device attempts toperform the RLM measurement in sub frames 0 and 5. That is, in a case inwhich the PSS and the SSS transmitted with sub frames 0 and 5 aredetected, the terminal device measures the reception power of the CRS inthe sub frames in which the PSS and the SSS are detected and performsthe RLM measurement. Conversely, in a case in which the PSS or the SSSis not detected in sub frames 0 and 5, the terminal device may notperform the RLM measurement in the sub frame in which the PSS or the SSSis not detected.

In addition, as still another example of the technique for the RLMmeasurement in LAA, the RLM measurement may be performed during a periodequivalent to a predetermined number of sub frames from a sub frame(unit period) in which a synchronization signal (initial signal)transmitted in the head of a downlink transmission burst is detected.The predetermined number of sub frames is one or more and is preferablyset with the RRC. Note that in a case in which it is notified orrecognized that the terminal device is operated in Japan, for example, 4is set as the predetermined number of sub frames. In addition, theinitial signal may be, for example, a signal sequence such as thePSS/SSS. Note that a part of the initial signal may be configured as,for example, a Zadoff-Chu sequence.

In addition, as still another example of the technique for the RLMmeasurement in LAA, a technique for performing the RLM measurement in asub frame with which the terminal device can recognize that a channel ora signal from a serving cell is transmitted can be exemplified. Forexample, in a case in which a predetermined channel or signal isdetected and a case in which average power of head OFDM symbols of subframes or slots exceeds a predetermined value or the like, the terminaldevice may recognize that the channel or the signal from the servingcell may be transmitted.

In addition, as still another example of the technique for the RLMmeasurement in LAA, a technique for performing the RLM measurement in adownlink sub frame after a predetermined number of sub frames from anuplink sub frame with which the terminal device transmits apredetermined uplink channel or uplink signal can be exemplified. Anexample of the predetermined uplink channel or uplink signal includes aPUCCH or the like including the PRACH, the SRS, and the SR. The downlinksub frame after the predetermined number of sub frames may be, forexample, a first downlink sub frame after four sub frames from theuplink sub frame.

Note that the foregoing techniques for the RLM measurement may becombined and applied. By combining two or more of the techniques, thenumber of sub frames in which the RLM measurement is performed increasesand measurement precision of the downlink quality becomes better.

Note that a measurement section used in LAA may be individually set. Forexample, in the measurement section used in an LAA cell, differentsetting from a measurement section used in a cell which is not the LAAcell may be performed.

In addition, an RLF timer used in LAA may be individually set. Forexample, as the RLF timer used in LAA, a different timer from the timerT310 or T313 described with reference to FIG. 15 may be set. The RLMtimer used in LAA may be set with, for example, the RRC. Note that inthe RLF timer used in LAA, a fixed value may be set or a preset valuemay be used.

Note that for the threshold Q_(out) and the threshold Q_(in) applied toLAA, the definition and the values of the threshold Q_(out) and thethreshold Q_(in) applied to a primary cell of LTE may be different. Asone example, the threshold Q_(out) used in LAA is defined, for example,at a level equivalent to 10% of a block error rate of the virtual PDCCHtransmission in which the PCFICH error is considered. As the virtualPDCCH, a PDCCH to which a CRC scrambled with a CC-RNTI is added isassumed. In addition, the threshold Q_(in) is defined, for example, at alevel sufficiently better than the threshold Q_(out) in the receptionquality and equivalent to 2% of the block error rate of the virtualPDCCH transmission in which the PCFICH error is considered. As thevirtual PDCCH, a PDCCH to which a CRC scrambled with a CC-RNTI is addedis assumed.

Note that the foregoing technique can also be applied similarly to NR inwhich the RS used to measure the downlink quality is not included in allthe sub frames.

Note that, in NR, the RLM measurement may be performed even in asecondary cell in addition to the primary cell and/or the primarysecondary cell. That is, the terminal device which can be connected toNR may be able to perform the RLM measurement in the secondary cell inaddition to the primary cell and/or the primary secondary cell.

In addition, in NR, the RLM measurement may be performed even in aneighbor cell (adjacent cell) in addition to the serving cell. That is,the terminal device which can be connected to NR may be able to performthe RLM measurement even in the neighbor cell in addition to the servingcell. Thus, since cell synchronization with the neighbor cell can beestablished in advance, the terminal device can realize high-speedhandover from the serving cell to the neighbor cell.

2. APPLICATION EXAMPLES

The technology according to the present disclosure can be applied tovarious products. For example, the base station device 1 may be realizedas any type of evolved Node B (eNB) such as a macro eNB or a small eNB.The small eNB may be an eNB that covers a cell, such as a pico eNB, amicro eNB, or a home (femto) eNB, smaller than a macro cell. Instead,the base station device 1 may be realized as another type of basestation such as a NodeB or a base transceiver station (BTS). The basestation device 1 may include a main entity (also referred to as a basestation device) that controls wireless communication and one or moreremote radio heads (RRHs) disposed at different locations from the mainentity. Further, various types of terminals to be described below mayoperate as the base station device 1 by performing a base stationfunction temporarily or permanently. Moreover, at least some of theconstituent elements of the base station device 1 may be realized in abase station device or a module for the base station device.

Further, for example, the terminal device 2 may be realized as a mobileterminal such as a smartphone, a tablet personal computer (PC), anotebook PC, a portable game terminal, a portable/dongle mobile routeror a digital camera, or an in-vehicle terminal such as a car navigationdevice. Further, the terminal device 2 may be realized as a terminalthat performs machine to machine (M2M) communication (also referred toas a machine type communication (MTC) terminal). Moreover, at least someof the constituent elements of the terminal device 2 may be realized ina module mounted on the terminal (for example, an integrated circuitmodule configured on one die).

2.1. Application Examples for Base Station First Application Example

FIG. 15 is a block diagram illustrating a first example of a schematicconfiguration of an eNB to which the technology according to the presentdisclosure may be applied. An eNB 800 includes one or more antennas 810and a base station apparatus 820. Each antenna 810 and the base stationapparatus 820 may be connected to each other via an RF cable.

Each of the antennas 810 includes a single or a plurality of antennaelements (e.g., a plurality of antenna elements constituting a MIMOantenna) and is used for the base station apparatus 820 to transmit andreceive a wireless signal. The eNB 800 may include the plurality of theantennas 810 as illustrated in FIG. 15 , and the plurality of antennas810 may, for example, correspond to a plurality of frequency bands usedby the eNB 800. It should be noted that while FIG. 15 illustrates anexample in which the eNB 800 includes the plurality of antennas 810, theeNB 800 may include the single antenna 810.

The base station apparatus 820 includes a controller 821, a memory 822,a network interface 823, and a wireless communication interface 825.

The controller 821 may be, for example, a CPU or a DSP, and operatesvarious functions of an upper layer of the base station apparatus 820.For example, the controller 821 generates a data packet from data in asignal processed by the wireless communication interface 825, andtransfers the generated packet via the network interface 823. Thecontroller 821 may generate a bundled packet by bundling data from aplurality of base band processors to transfer the generated bundledpacket. Further, the controller 821 may also have a logical function ofperforming control such as radio resource control, radio bearer control,mobility management, admission control, and scheduling. Further, thecontrol may be performed in cooperation with a surrounding eNB or a corenetwork node. The memory 822 includes a RAM and a ROM, and stores aprogram executed by the controller 821 and a variety of control data(such as, for example, terminal list, transmission power data, andscheduling data).

The network interface 823 is a communication interface for connectingthe base station apparatus 820 to the core network 824. The controller821 may communicate with a core network node or another eNB via thenetwork interface 823. In this case, the eNB 800 may be connected to acore network node or another eNB through a logical interface (e.g., S1interface or X2 interface). The network interface 823 may be a wiredcommunication interface or a wireless communication interface forwireless backhaul. In the case where the network interface 823 is awireless communication interface, the network interface 823 may use ahigher frequency band for wireless communication than a frequency bandused by the wireless communication interface 825.

The wireless communication interface 825 supports a cellularcommunication system such as long term evolution (LTE) or LTE-Advanced,and provides wireless connection to a terminal located within the cellof the eNB 800 via the antenna 810. The wireless communication interface825 may typically include a base band (BB) processor 826, an RF circuit827, and the like. The BB processor 826 may, for example, performencoding/decoding, modulation/demodulation, multiplexing/demultiplexing,and the like, and performs a variety of signal processing on each layer(e.g., L1, medium access control (MAC), radio link control (RLC), andpacket data convergence protocol (PDCP)). The BB processor 826 may havepart or all of the logical functions as described above instead of thecontroller 821. The BB processor 826 may be a module including a memoryhaving a communication control program stored therein, a processor toexecute the program, and a related circuit, and the function of the BBprocessor 826 may be changeable by updating the program. Further, themodule may be a card or blade to be inserted into a slot of the basestation apparatus 820, or a chip mounted on the card or the blade.Meanwhile, the RF circuit 827 may include a mixer, a filter, anamplifier, and the like, and transmits and receives a wireless signalvia the antenna 810.

The wireless communication interface 825 may include a plurality of theBB processors 826 as illustrated in FIG. 15 , and the plurality of BBprocessors 826 may, for example, correspond to a plurality of frequencybands used by the eNB 800. Further, the wireless communication interface825 may also include a plurality of the RF circuits 827, as illustratedin FIG. 15 , and the plurality of RF circuits 827 may, for example,correspond to a plurality of antenna elements. Note that FIG. 15illustrates an example in which the wireless communication interface 825includes the plurality of BB processors 826 and the plurality of RFcircuits 827, but the wireless communication interface 825 may includethe single BB processor 826 or the single RF circuit 827.

In the eNB 800 illustrated in FIG. 15 , one or more constituent elementsof the higher layer processing unit 101 and the control unit 103described with reference to FIG. 8 may be implemented in the wirelesscommunication interface 825. Alternatively, at least some of theconstituent elements may be implemented in the controller 821. As oneexample, a module including a part or the whole of (for example, the BBprocessor 826) of the wireless communication interface 825 and/or thecontroller 821 may be implemented on the eNB 800. The one or moreconstituent elements in the module may be implemented in the module. Inthis case, the module may store a program causing a processor tofunction as the one more constituent elements (in other words, a programcausing the processor to execute operations of the one or moreconstituent elements) and execute the program. As another example, aprogram causing the processor to function as the one or more constituentelements may be installed in the eNB 800, and the wireless communicationinterface 825 (for example, the BB processor 826) and/or the controller821 may execute the program. In this way, the eNB 800, the base stationdevice 820, or the module may be provided as a device including the oneor more constituent elements and a program causing the processor tofunction as the one or more constituent elements may be provided. Inaddition, a readable recording medium on which the program is recordedmay be provided.

Further, in the eNB 800 illustrated in FIG. 15 , the receiving unit 105and the transmitting unit 107 described with reference to FIG. 8 may beimplemented in the wireless communication interface 825 (for example,the RF circuit 827). Further, the transceiving antenna 109 may beimplemented in the antenna 810. Further, the network communication unit130 may be implemented in the controller 821 and/or the networkinterface 823.

Second Application Example

FIG. 16 is a block diagram illustrating a second example of a schematicconfiguration of an eNB to which the technology according to the presentdisclosure may be applied. An eNB 830 includes one or more antennas 840,a base station apparatus 850, and an RRH 860. Each of the antennas 840and the RRH 860 may be connected to each other via an RF cable. Further,the base station apparatus 850 and the RRH 860 may be connected to eachother by a high speed line such as optical fiber cables.

Each of the antennas 840 includes a single or a plurality of antennaelements (e.g., antenna elements constituting a MIMO antenna), and isused for the RRH 860 to transmit and receive a wireless signal. The eNB830 may include a plurality of the antennas 840 as illustrated in FIG.16 , and the plurality of antennas 840 may, for example, correspond to aplurality of frequency bands used by the eNB 830. Note that FIG. 16illustrates an example in which the eNB 830 includes the plurality ofantennas 840, but the eNB 830 may include the single antenna 840.

The base station apparatus 850 includes a controller 851, a memory 852,a network interface 853, a wireless communication interface 855, and aconnection interface 857. The controller 851, the memory 852, and thenetwork interface 853 are similar to the controller 821, the memory 822,and the network interface 823 described with reference to FIG. 15 .

The wireless communication interface 855 supports a cellularcommunication system such as LTE and LTE-Advanced, and provides wirelessconnection to a terminal located in a sector corresponding to the RRH860 via the RRH 860 and the antenna 840. The wireless communicationinterface 855 may typically include a BB processor 856 or the like. TheBB processor 856 is similar to the BB processor 826 described withreference to FIG. 15 except that the BB processor 856 is connected to anRF circuit 864 of the RRH 860 via the connection interface 857. Thewireless communication interface 855 may include a plurality of the BBprocessors 856, as illustrated in FIG. 15 , and the plurality of BBprocessors 856 may, for example, correspond to a plurality of frequencybands used by the eNB 830. Note that FIG. 16 illustrates an example inwhich the wireless communication interface 855 includes the plurality ofBB processors 856, but the wireless communication interface 855 mayinclude the single BB processor 856.

The connection interface 857 is an interface for connecting the basestation apparatus 850 (wireless communication interface 855) to the RRH860. The connection interface 857 may be a communication module forcommunication on the high speed line which connects the base stationapparatus 850 (wireless communication interface 855) to the RRH 860.

Further, the RRH 860 includes a connection interface 861 and a wirelesscommunication interface 863.

The connection interface 861 is an interface for connecting the RRH 860(wireless communication interface 863) to the base station apparatus850. The connection interface 861 may be a communication module forcommunication on the high speed line.

The wireless communication interface 863 transmits and receives awireless signal via the antenna 840. The wireless communicationinterface 863 may typically include the RF circuit 864 or the like. TheRF circuit 864 may include a mixer, a filter, an amplifier and the like,and transmits and receives a wireless signal via the antenna 840. Thewireless communication interface 863 may include a plurality of the RFcircuits 864 as illustrated in FIG. 16 , and the plurality of RFcircuits 864 may, for example, correspond to a plurality of antennaelements. Note that FIG. 16 illustrates an example in which the wirelesscommunication interface 863 includes the plurality of RF circuits 864,but the wireless communication interface 863 may include the single RFcircuit 864.

In the eNB 830 illustrated in FIG. 16 , one or more constituent elementsof the higher layer processing unit 101 and the control unit 103described with reference to FIG. 8 may be implemented in the wirelesscommunication interface 855 and/or the wireless communication interface863. Alternatively, at least some of the constituent elements may beimplemented in the controller 851. As one example, a module including apart or the whole of (for example, the BB processor 856) of the wirelesscommunication interface 855 and/or the controller 851 may be implementedon the eNB 830. The one or more constituent elements may be implementedin the module. In this case, the module may store a program causing aprocessor to function as the one more constituent elements (in otherwords, a program causing the processor to execute operations of the oneor more constituent elements) and execute the program. As anotherexample, a program causing the processor to function as the one or moreconstituent elements may be installed in the eNB 830, and the wirelesscommunication interface 855 (for example, the BB processor 856) and/orthe controller 851 may execute the program. In this way, the eNB 830,the base station device 850, or the module may be provided as a deviceincluding the one or more constituent elements and a program causing theprocessor to function as the one or more constituent elements may beprovided. In addition, a readable recording medium on which the programis recorded may be provided.

Further, in the eNB 830 illustrated in FIG. 16 , for example, thereceiving unit 105 and the transmitting unit 107 described withreference to FIG. 8 may be implemented in the wireless communicationinterface 863 (for example, the RF circuit 864). Further, thetransceiving antenna 109 may be implemented in the antenna 840. Further,the network communication unit 130 may be implemented in the controller851 and/or the network interface 853.

2.2 Application Examples for Terminal Apparatus First ApplicationExample

FIG. 17 is a block diagram illustrating an example of a schematicconfiguration of a smartphone 900 to which the technology according tothe present disclosure may be applied. The smartphone 900 includes aprocessor 901, a memory 902, a storage 903, an external connectioninterface 904, a camera 906, a sensor 907, a microphone 908, an inputdevice 909, a display device 910, a speaker 911, a wirelesscommunication interface 912, one or more antenna switches 915, one ormore antennas 916, a bus 917, a battery 918, and an auxiliary controller919.

The processor 901 may be, for example, a CPU or a system on chip (SoC),and controls the functions of an application layer and other layers ofthe smartphone 900. The memory 902 includes a RAM and a ROM, and storesa program executed by the processor 901 and data. The storage 903 mayinclude a storage medium such as semiconductor memories and hard disks.The external connection interface 904 is an interface for connecting thesmartphone 900 to an externally attached device such as memory cards anduniversal serial bus (USB) devices.

The camera 906 includes, for example, an image sensor such as chargecoupled devices (CCDs) and complementary metal oxide semiconductor(CMOS), and generates a captured image. The sensor 907 may include asensor group including, for example, a positioning sensor, a gyrosensor, a geomagnetic sensor, an acceleration sensor and the like. Themicrophone 908 converts a sound that is input into the smartphone 900 toan audio signal. The input device 909 includes, for example, a touchsensor which detects that a screen of the display device 910 is touched,a key pad, a keyboard, a button, a switch or the like, and accepts anoperation or an information input from a user. The display device 910includes a screen such as liquid crystal displays (LCDs) and organiclight emitting diode (OLED) displays, and displays an output image ofthe smartphone 900. The speaker 911 converts the audio signal that isoutput from the smartphone 900 to a sound.

The wireless communication interface 912 supports a cellularcommunication system such as LTE or LTE-Advanced, and performs wirelesscommunication. The wireless communication interface 912 may typicallyinclude the BB processor 913, the RF circuit 914, and the like. The BBprocessor 913 may, for example, perform encoding/decoding,modulation/demodulation, multiplexing/demultiplexing, and the like, andperforms a variety of types of signal processing for wirelesscommunication. On the other hand, the RF circuit 914 may include amixer, a filter, an amplifier, and the like, and transmits and receivesa wireless signal via the antenna 916. The wireless communicationinterface 912 may be a one-chip module in which the BB processor 913 andthe RF circuit 914 are integrated. The wireless communication interface912 may include a plurality of BB processors 913 and a plurality of RFcircuits 914 as illustrated in FIG. 17 . Note that FIG. 17 illustratesan example in which the wireless communication interface 912 includes aplurality of BB processors 913 and a plurality of RF circuits 914, butthe wireless communication interface 912 may include a single BBprocessor 913 or a single RF circuit 914.

Further, the wireless communication interface 912 may support othertypes of wireless communication system such as a short range wirelesscommunication system, a near field communication system, and a wirelesslocal area network (LAN) system in addition to the cellularcommunication system, and in this case, the wireless communicationinterface 912 may include the BB processor 913 and the RF circuit 914for each wireless communication system.

Each antenna switch 915 switches a connection destination of the antenna916 among a plurality of circuits (for example, circuits for differentwireless communication systems) included in the wireless communicationinterface 912.

Each of the antennas 916 includes one or more antenna elements (forexample, a plurality of antenna elements constituting a MIMO antenna)and is used for transmission and reception of the wireless signal by thewireless communication interface 912. The smartphone 900 may include aplurality of antennas 916 as illustrated in FIG. 17 . Note that FIG. 17illustrates an example in which the smartphone 900 includes a pluralityof antennas 916, but the smartphone 900 may include a single antenna916.

Further, the smartphone 900 may include the antenna 916 for eachwireless communication system. In this case, the antenna switch 915 maybe omitted from a configuration of the smartphone 900.

The bus 917 connects the processor 901, the memory 902, the storage 903,the external connection interface 904, the camera 906, the sensor 907,the microphone 908, the input device 909, the display device 910, thespeaker 911, the wireless communication interface 912, and the auxiliarycontroller 919 to each other. The battery 918 supplies electric power toeach block of the smartphone 900 illustrated in FIG. 17 via a feederline that is partially illustrated in the figure as a dashed line. Theauxiliary controller 919, for example, operates a minimally necessaryfunction of the smartphone 900 in a sleep mode.

In the smartphone 900 illustrated in FIG. 17 , one or more constituentelements of the higher layer processing unit 201 and the control unit203 described with reference to FIG. 9 described with reference to FIG.9 may be implemented in the wireless communication interface 912.Alternatively, at least some of the constituent elements may beimplemented in the processor 901 or the auxiliary controller 919. As oneexample, a module including a part or the whole of (for example, the BBprocessor 913) of the wireless communication interface 912, theprocessor 901, and/or the auxiliary controller 919 may be implemented onthe smartphone 900. The one or more constituent elements may beimplemented in the module. In this case, the module may store a programcausing a processor to function as the one more constituent elements (inother words, a program causing the processor to execute operations ofthe one or more constituent elements) and execute the program. Asanother example, a program causing the processor to function as the oneor more constituent elements may be installed in the smartphone 900, andthe wireless communication interface 912 (for example, the BB processor913), the processor 901, and/or the auxiliary controller 919 may executethe program. In this way, the smartphone 900 or the module may beprovided as a device including the one or more constituent elements anda program causing the processor to function as the one or moreconstituent elements may be provided. In addition, a readable recordingmedium on which the program is recorded may be provided.

Further, in the smartphone 900 illustrated in FIG. 17 , for example, thereceiving unit 205 and the transmitting unit 207 described withreference to FIG. 9 may be implemented in the wireless communicationinterface 912 (for example, the RF circuit 914). Further, thetransceiving antenna 209 may be implemented in the antenna 916.

Second Application Example

FIG. 18 is a block diagram illustrating an example of a schematicconfiguration of a car navigation apparatus 920 to which the technologyaccording to the present disclosure may be applied. The car navigationapparatus 920 includes a processor 921, a memory 922, a globalpositioning system (GPS) module 924, a sensor 925, a data interface 926,a content player 927, a storage medium interface 928, an input device929, a display device 930, a speaker 931, a wireless communicationinterface 933, one or more antenna switches 936, one or more antennas937, and a battery 938.

The processor 921 may be, for example, a CPU or an SoC, and controls thenavigation function and the other functions of the car navigationapparatus 920. The memory 922 includes a RAM and a ROM, and stores aprogram executed by the processor 921 and data.

The GPS module 924 uses a GPS signal received from a GPS satellite tomeasure the position (e.g., latitude, longitude, and altitude) of thecar navigation apparatus 920. The sensor 925 may include a sensor groupincluding, for example, a gyro sensor, a geomagnetic sensor, abarometric sensor and the like. The data interface 926 is, for example,connected to an in-vehicle network 941 via a terminal that is notillustrated, and acquires data such as vehicle speed data generated onthe vehicle side.

The content player 927 reproduces content stored in a storage medium(e.g., CD or DVD) inserted into the storage medium interface 928. Theinput device 929 includes, for example, a touch sensor which detectsthat a screen of the display device 930 is touched, a button, a switchor the like, and accepts operation or information input from a user. Thedisplay device 930 includes a screen such as LCDs and OLED displays, anddisplays an image of the navigation function or the reproduced content.The speaker 931 outputs a sound of the navigation function or thereproduced content.

The wireless communication interface 933 supports a cellularcommunication system such as LTE or LTE-Advanced, and performs wirelesscommunication. The wireless communication interface 933 may typicallyinclude the BB processor 934, the RF circuit 935, and the like. The BBprocessor 934 may, for example, perform encoding/decoding,modulation/demodulation, multiplexing/demultiplexing, and the like, andperforms a variety of types of signal processing for wirelesscommunication. On the other hand, the RF circuit 935 may include amixer, a filter, an amplifier, and the like, and transmits and receivesa wireless signal via the antenna 937. The wireless communicationinterface 933 may be a one-chip module in which the BB processor 934 andthe RF circuit 935 are integrated. The wireless communication interface933 may include a plurality of BB processors 934 and a plurality of RFcircuits 935 as illustrated in FIG. 18 . Note that FIG. 18 illustratesan example in which the wireless communication interface 933 includes aplurality of BB processors 934 and a plurality of RF circuits 935, butthe wireless communication interface 933 may include a single BBprocessor 934 or a single RF circuit 935.

Further, the wireless communication interface 933 may support othertypes of wireless communication system such as a short range wirelesscommunication system, a near field communication system, and a wirelessLAN system in addition to the cellular communication system, and in thiscase, the wireless communication interface 933 may include the BBprocessor 934 and the RF circuit 935 for each wireless communicationsystem.

Each antenna switch 936 switches a connection destination of the antenna937 among a plurality of circuits (for example, circuits for differentwireless communication systems) included in the wireless communicationinterface 933.

Each of the antennas 937 includes one or more antenna elements (forexample, a plurality of antenna elements constituting a MIMO antenna)and is used for transmission and reception of the wireless signal by thewireless communication interface 933. The car navigation apparatus 920may include a plurality of antennas 937 as illustrated in FIG. 18 . Notethat FIG. 18 illustrates an example in which the car navigationapparatus 920 includes a plurality of antennas 937, but the carnavigation apparatus 920 may include a single antenna 937.

Further, the car navigation apparatus 920 may include the antenna 937for each wireless communication system. In this case, the antenna switch936 may be omitted from a configuration of the car navigation apparatus920.

The battery 938 supplies electric power to each block of the carnavigation apparatus 920 illustrated in FIG. 18 via a feeder line thatis partially illustrated in the figure as a dashed line. Further, thebattery 938 accumulates the electric power supplied from the vehicle.

In the car navigation 920 illustrated in FIG. 18 , one or moreconstituent elements of the higher layer processing unit 201 and thecontrol unit 203 described with reference to FIG. 9 described withreference to FIG. 9 may be implemented in the wireless communicationinterface 933. Alternatively, at least some of the constituent elementsmay be implemented in the processor 921. As one example, a moduleincluding a part or the whole of (for example, the BB processor 934) ofthe wireless communication interface 933 and/or the processor 921 may beimplemented on the car navigation 920. The one or more constituentelements may be implemented in the module. In this case, the module maystore a program causing a processor to function as the one moreconstituent elements (in other words, a program causing the processor toexecute operations of the one or more constituent elements) and executethe program. As another example, a program causing the processor tofunction as the one or more constituent elements may be installed in thecar navigation 920, and the wireless communication interface 933 (forexample, the BB processor 934) and/or the processor 921 may execute theprogram. In this way, the car navigation 920 or the module may beprovided as a device including the one or more constituent elements anda program causing the processor to function as the one or moreconstituent elements may be provided. In addition, a readable recordingmedium on which the program is recorded may be provided.

Further, in the car navigation 920 illustrated in FIG. 18 , for example,the receiving unit 205 and the transmitting unit 207 described withreference to FIG. 9 may be implemented in the wireless communicationinterface 933 (for example, the RF circuit 935). Further, thetransceiving antenna 209 may be implemented in the antenna 937.

The technology of the present disclosure may also be realized as anin-vehicle system (or a vehicle) 940 including one or more blocks of thecar navigation apparatus 920, the in-vehicle network 941, and a vehiclemodule 942. That is, the in-vehicle system (or a vehicle) 940 may beprovided as a device that includes at least one of the higher layerprocessing unit 201, the control unit 203, the receiving unit 205, orthe transmitting unit 207. The vehicle module 942 generates vehicle datasuch as vehicle speed, engine speed, and trouble information, andoutputs the generated data to the in-vehicle network 941.

3. CONCLUSION

As described above, in a situation in which a reference signal such as aCRS is discontinuously transmitted as in LAA or NR (that is, a situationin which a sub frame with which a reference signal is not transmittedcan occur), a communication device (the terminal device) according tothe present embodiment acquires information regarding communicationquality on the basis of the reference signal targeting a period in whichthe reference signal is transmitted (for example, a sub frame). Notethat, a period in which the reference signal is transmitted may bespecified on the basis of, for example, a detection result of asynchronization signal such as a DS or information regarding the periodmay be notified of by the base station. In addition, the period in whichthe reference signal is transmitted may be set in advance. In this way,in the present embodiment, the acquisition of the information regardingthe communication quality (for example, measurement of communicationquality) is performed in the unit period (for example, the sub frame) inwhich the predetermined reference signal is transmitted.

According to the foregoing configuration, in the communication deviceaccording to the present embodiment, a situation in which a period inwhich the reference signal is not transmitted is considered to be anacquisition target of information regarding the communication qualitycan be prevented from occurring in a situation in which the referencesignal is discontinuously transmitted. Thus, in the communication deviceaccording to the present embodiment, more stable downlinksynchronization or RLM measurement can be realized even in a situationin which the reference signal such as the CRS is not transmitted duringall the unit periods (for example, the sub frames).

The preferred embodiment(s) of the present disclosure has/have beendescribed above with reference to the accompanying drawings, whilst thepresent disclosure is not limited to the above examples. A personskilled in the art may find various alterations and modifications withinthe scope of the appended claims, and it should be understood that theywill naturally come under the technical scope of the present disclosure.

Further, the effects described in this specification are merelyillustrative or exemplified effects, and are not limitative. That is,with or in the place of the above effects, the technology according tothe present disclosure may achieve other effects that are clear to thoseskilled in the art from the description of this specification.

Additionally, the present technology may also be configured as below.

(1)

A communication device including:

a communication unit configured to perform wireless communication; and

an acquisition unit configured to acquire information regardingcommunication quality of the wireless communication targeting a periodin which a reference signal is transmitted on the basis of the referencesignal that is discontinuously transmitted.

(2)

The communication device according to (1),

in which, in a series of periods including a plurality of unit periods,the reference signal is selectively transmitted during at least some ofthe unit periods, and

the acquisition unit acquires information regarding the communicationquality targeting the unit period in which the reference signal istransmitted in the series of periods.

(3)

The communication device according to (1) or (2), in which theacquisition unit acquires information regarding the communicationquality targeting a period on the basis of a detection result of apredetermined synchronization signal.

(4)

The communication device according to any one of (1) to (3), in whichthe acquisition unit acquires information regarding the communicationquality targeting a period specified on the basis of informationnotified of by a base station.

(5)

The communication device according to any one of (1) to (4), in whichthe acquisition unit acquires information regarding the communicationquality targeting a predetermined period in which a predeterminedsynchronization signal is transmitted.

(6)

The communication device according to (1), in which the acquisition unitacquires information regarding the communication quality targeting aperiod specified on the basis of a detection result of a predeterminedsynchronization signal transmitted in a downlink signal from a basestation.

(7)

The communication device according to (6), in which, in a series ofperiods including a plurality of unit periods, the acquisition unitacquires information regarding the communication quality targeting apredetermined number of the unit periods among the unit periods in whichthe synchronization signal is detected.

(8)

The communication device according to any one of (1) to (7), including:

a control unit configured to control the wireless communication with abase station on the basis of the acquired information regarding thecommunication quality,

in which the control unit disconnects or reestablishes the wirelesscommunication with the base station in a case in which a periodindicating that the communication quality is equal to or less than athreshold exceeds a predetermined time.

(9)

The communication device according to (8), in which setting of a timerfor measuring the predetermined time is different from setting of thetimer in a communication scheme of consecutively transmitting thereference signal.

(10)

The communication device according to any one of (1) to (9), in whichthe acquisition unit acquires information regarding the communicationquality, acquires information regarding the communication qualitytargeting a period in which the reference signal is transmitted on thebasis of the reference signal that is discontinuously transmitted, in acase in which the wireless communication is performed using anunlicensed band.

(11)

The communication device according to any one of (1) to (10), in whichthe acquisition unit acquires information regarding the communicationquality targeting a period in which the reference signal is transmittedon the basis of the reference signal that is discontinuouslytransmitted, in a case in which the wireless communication is performedon the basis of a communication scheme of enabling a sub carrierinterval and a symbol length to be controlled.

(12)

The communication device according to any one of (1) to (11), in whichthe acquisition unit acquires information regarding the communicationquality with regard to each of a primary cell and a secondary cell.

(13)

The communication device according to any one of (1) to (11), in whichthe acquisition unit acquires information regarding the communicationquality with regard to each of a secondary cell and at least any of aprimary cell or a primary secondary cell.

(14)

The communication device according to any one of (1) to (11), in whichthe acquisition unit acquires information regarding the communicationquality with regard to each of a serving cell and a neighbor cell.

(15)

A communication device including:

a communication unit configured to perform wireless communication; and

a control unit configured to control a reference signal that isdiscontinuously transmitted and used to measure communication quality ofthe wireless communication such that information for directly orindirectly specifying a period in which the reference signal istransmitted is transmitted to a terminal device.

(16)

The communication device according to (15), in which the control unitperforms control such that the reference signal is transmitted to theterminal device during a period in which transmission of a predeterminedsynchronization signal is set.

(17)

The communication device according to (15) or (16), in which the controlunit performs control such that information regarding a period in whichtransmission of the reference signal is allocated is transmitted to theterminal device.

(18)

The communication device according to any one of (15) to (17), in whichthe control unit performs control such that the reference signal istransmitted to the terminal device during a predetermined period inwhich a predetermined synchronization signal is transmitted.

(19)

A communication method including:

performing wireless communication; and

acquiring, by a computer, information regarding communication quality ofthe wireless communication targeting a period in which a referencesignal is transmitted on the basis of the reference signal that isdiscontinuously transmitted.

(20)

A communication method including:

performing wireless communication; and

controlling, by a computer, a reference signal that is discontinuouslytransmitted and used to measure communication quality of the wirelesscommunication such that information for directly or indirectlyspecifying a period in which the reference signal is transmitted istransmitted to a terminal device.

(21)

A program causing a computer to:

perform wireless communication; and

acquire information regarding communication quality of the wirelesscommunication targeting a period in which a reference signal istransmitted on the basis of the reference signal that is discontinuouslytransmitted.

(22)

A program causing a computer to:

perform wireless communication; and

control a reference signal that is discontinuously transmitted and usedto measure communication quality of the wireless communication such thatinformation for directly or indirectly specifying a period in which thereference signal is transmitted is transmitted to a terminal device.

REFERENCE SIGNS LIST

-   1 base station device-   101 higher layer processing unit-   103 control unit-   105 receiving unit-   1051 decoding unit-   1053 demodulating unit-   1055 demultiplexing unit-   1057 wireless receiving unit-   1059 channel measuring unit-   107 transmitting unit-   1071 encoding unit-   1073 modulating unit-   1075 multiplexing unit-   1077 wireless transmitting unit-   1079 link reference signal generating unit-   109 transceiving antenna-   130 network communication unit-   2 terminal device-   201 higher layer processing unit-   203 control unit-   205 receiving unit-   2051 decoding unit-   2053 demodulating unit-   2055 demultiplexing unit-   2057 wireless receiving unit-   2059 channel measuring unit-   207 transmitting unit-   2071 encoding unit-   2073 modulating unit-   2075 multiplexing unit-   2077 wireless transmitting unit-   2079 link reference signal generating unit-   209 transceiving antenna

1. A user equipment comprising: a radio transceiver configured toperform wireless communication in a first cell served by a first basestation and a second cell served by a second base station; and circuitryconfigured to: perform Radio Link Monitoring (RLM) using downlinkphysical signals transmitted on the first cell served by the first basestation, wherein the downlink physical signals include PrimarySynchronization Signal (PSS), Secondary Synchronization Signal (SSS),and a downlink Demodulation Reference Signal (DMRS), measure a radiolink quality using the downlink physical signals, evaluate the radiolink quality against thresholds Qout and Qin, on condition that theradio link quality is worse than the threshold Qout, indicateout-of-sync to higher layers from a physical layer, on condition thatthe radio link quality is better than the threshold Qin, indicatein-sync to the higher layers from the physical layer, start a firsttimer when the out-of-sync is consecutively indicated to the higherlayers from the physical layer, and determine that a radio link failureoccurs in the first cell served by the first base station in a casewhere the first timer expires without consecutive in-sync indications,wherein the first timer used to determine whether the radio link failureoccurs in the first cell served by the first base station is differentfrom a second timer used to determine whether a radio link failureoccurs in the second cell served by the second base station.
 2. The userequipment according to claim 1, wherein the downlink physical signalsincluding the PSS, the SSS and the downlink DMRS are used by the userequipment for the RLM within a certain duration indicated in units ofmillisecond, and the certain duration is configured by Radio ResourceControl (RRC) layer.
 3. The user equipment according to claim 1, whereinthe first cell corresponds to a Radio Access Technology (RAT) that isdifferent of a RAT corresponding the second cell.
 4. The user equipmentaccording to claim 3, wherein the first cell corresponds to New Radio(NR), and the second cell corresponds to Long Term Evolution (LTE),wherein the circuitry configured to perform Radio Link Monitoring (RLM)using downlink physical signals transmitted on the second cell, whereinthe downlink physical signals include cell-specific reference signal(CRS).
 5. A radio communication device in a base station, the radiocommunication device comprising: a radio transceiver configured toperform wireless communication in one or more serving cells; andcircuitry configured to control the radio transceiver to transmitdownlink physical signals on a first cell among the one or more servingcells, wherein the downlink physical signals include PrimarySynchronization Signal (PSS), Secondary Synchronization Signal (SSS),and a downlink Demodulation Reference Signal (DMRS), wherein thedownlink physical signals are used by the user equipment to: measure aradio link quality using the downlink physical signals, evaluate theradio link quality against thresholds Qout and Qin, on condition thatthe radio link quality is worse than the threshold Qout, indicateout-of-sync to higher layers from a physical layer, on condition thatthe radio link quality is better than the threshold Qin, indicatein-sync to the higher layers than the physical layer, start a firsttimer when the out-of-sync is consecutively indicated to the higherlayers from the physical layer, and determine that a radio link failureoccurs in the first cell in a case where the first timer expires withoutconsecutive in-sync indications, wherein the first timer used todetermine whether the radio link failure occurs in the first cell isdifferent from a second timer used to determine whether a radio linkfailure occurs in a second cell served by another base station.
 6. Theradio communication device in the base station according to claim 5,wherein the downlink physical signals including the PSS, the SSS and thedownlink DMRS are used by the user equipment for the RLM within acertain duration indicated in units of millisecond, and the certainduration is configured by Radio Resource Control (RRC) layer.
 7. Theradio communication device in the base station according to claim 5,wherein the first cell corresponds to a Radio Access Technology (RAT)that is different of a RAT corresponding the second cell.
 8. A methodfor a user equipment, the method comprising: performing wirelesscommunication in a first cell served by a first base station and asecond cell served by a second base station; performing, usingcircuitry, Radio Link Monitoring (RLM) using downlink physical signalstransmitted on the first cell served by the first base station, whereinthe downlink physical signals include Primary Synchronization Signal(PSS), Secondary Synchronization Signal (SSS), and a downlinkDemodulation Reference Signal (DMRS), measuring a radio link qualityusing the downlink physical signals, evaluating the radio link qualityagainst thresholds Qout and Qin, on condition that the radio linkquality is worse than the threshold Qout, indicate out-of-sync to higherlayers from a physical layer, on condition that the radio link qualityis better than the threshold Qin, indicate in-sync to the higher layersfrom the physical layer, starting a first timer when the out-of-sync isconsecutively indicated to the higher layers from the physical layer,and determining that a radio link failure occurs in the first cellserved by the first base station in a case where the first timer expireswithout consecutive in-sync indications, wherein the first timer used todetermine whether the radio link failure occurs in the first cell servedby the first base station is different from a second timer used todetermine whether a radio link failure occurs in the second cell servedby the second base station.
 9. A method for a base station, the methodcomprising: performing, using radio transceiver, a radio transceiverconfigured to perform wireless communication in one or more servingcells; and transmitting downlink physical signals on a first cell amongthe one or more serving cells, wherein the downlink physical signalsinclude Primary Synchronization Signal (PSS), Secondary SynchronizationSignal (SSS), and a downlink Demodulation Reference Signal (DMRS),wherein the downlink physical signals are used by the user equipment to:measure a radio link quality using the downlink physical signals,evaluate the radio link quality against thresholds Qout and Qin, oncondition that the radio link quality is worse than the threshold Qout,indicate out-of-sync to higher layers from a physical layer, oncondition that the radio link quality is better than the threshold Qin,indicate in-sync to the higher layers than the physical layer, start afirst timer when the out-of-sync is consecutively indicated to thehigher layers from the physical layer, and determine that a radio linkfailure occurs in the first cell in a case where the first timer expireswithout consecutive in-sync indications, wherein the first timer used todetermine whether the radio link failure occurs in the first cell isdifferent from a second timer used to determine whether a radio linkfailure occurs in a second cell served by another base station.